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Crash: Air France A332 over Atlantic on Jun 1st 2009, aircraft impacted ocean
| By Simon Hradecky, created Tuesday, Jun 2nd 2009 13:30Z, last updated Monday, Jun 15th 2009 16:10Z  | Debris of June 4th probably belonging to a ship
(Photo: FAB) |
Forca Aerea Brasileira (FAB) have confirmed in a press release, that one of the Hercules C-130 search airplanes sighted metallic and non-metallic debris on the ocean surface about 650km northnortheast of Fernando de Noronha Island at around 09:49Z. Two locations, about 60km apart have been identified.
The debris has been identified as an airplane seat, small white pieces, an orange ball, a drum and traces of oil and kerosene.
The Brasilian government now assumes, that these parts belonged to the Air France Airbus and confirms the crash.
The FAB announced, that the crash will be investigated under the lead of the French BEA with the support by Brazil's CENIPA (Centro de Investigação e Prevenção de Acidentes Aeronáuticos, Center for Investigation and Prevention of Aviation Accidents).
The BEA said, 20 investigators supported by 30 engineers from Air France and Airbus Industries have started to collect evidence. A team has been sent to Brazil to secure and analyse recordings of air traffic control frequencies and other evidence in Brazil.
The NTSB said, they have accepted an invitation by the BEA to assist in the investigation and have dispatched Bill English as their representative joined by engineers from the FAA, General Electrics (manufacturer of the CF6 engines) and Honeywell.
On Jun 4th the FAB announced, that they have found debris around 510km northnortheast of Fernando de Noronha. A cargo pallet of about 2.5 square meters and two buoys were recovered. Seven hours later the FAB however had to report, that the recovered debris did not belong to the Air France Airbus.
The BEA announced on June 5th, that so far only these facts have been verified:
- location near the planned route over the Atlantic in the vicinity of significant convective cells characteristic for the equatorial region
- from start of the automatic message transmissions the reported measured speeds were inconsistent.
Airbus Industries reminded all operators of Airbus Aircraft series A300 to A380 of the operational, abnormal and emergency procedures in the relevant Flight Crew Operation Manuals and Quick Reference Manuals regarding flying with unreliable airspeed.
A press conference of BEA on June 6th confirmed, that a total of 24 ACARS messages, 14 within the first minute at 02:10Z, indicating system faults, arrived from the airplane. The message show inconsistencies in the air speeds measured by the three pitot systems of the aircraft rendering the air speed indications unreliable. The BEA however cautioned, that those messages don't say anything about the causes and are not meant as a tool to aid investigations, but mainly reflect the system status and don't tell anything about the why. Although it appears probable, that the messages and the loss of the airplane are related, there is no confirmation of a casual link between the two events. Weather experts of Meteo France said, that the weather development on June 1st (UTC) within the InterTropical Convergence Zone was normal with no anomalies, there was no evidence, that AF-447 encountered a storm of extraordinary intensity. Weather developments were more intense in the days surrounding the accident day.
In the press conference the BEA said, that three methodes of finding the black boxes are currently employed: two ships have been equipped with acoustic equipment from the USA to be able to detect the 160dB(A) signal from the black boxes assumed to be at 4600 meters depth of the ocean. Another "ordinary warship" is tracking the area as well as a nuclear submarine.
BEA also said, that Airbus Industries had already recommended a retrofit of the pitot tubes of the airplane, F-GZCP however had not yet received that new design pitot tubes. Air France is still in the process of replacing the pitot tubes on all their aircraft.
A passenger on board of a TAM Linhas Aereas Airbus A330-200 registration PT-MVH performing flight JJ-8098 from Sao Paulo Guarulhos (Brazil) to Paris Charles de Gaulle (France) bound to land in Paris about 40 minutes past AF-447 reported, that they were about 4 hours into their flight, when the airplane experienced severe turbulence and began to violently shake. The pilots performed an emergency descent to get into calmer air. Only after about 30 minutes the turbulence ended. Subsequently the airplane reached Paris without further incident.
More details of the ACARS messages have become available on June 5th and suggest following events while the airplane was in cruise (note, there is no message regarding electrics, hydraulics or engine problems):
| 02:10Z: | Autothrust off | | | Autopilot off | | | FBW alternate law | | | Rudder Travel Limiter Fault | | | TCAS fault due to antenna fault | | | Flight Envelope Computation warning | | | All pitot static ports lost | | 02:11Z: | Failure of all three ADIRUs | | | Failure of gyros of ISIS (attitude information lost) | | 02:12Z: | ADIRUs Air Data disagree | | 02:13Z: | Flight Management, Guidance and Envelope Computer fault | | | PRIM 1 fault | | | SEC 1 fault | | 02:14Z: | Cabin Pressure Controller fault (cabin vertical speed) |
There have been at least two similiar incidents preceding AF-447 (dates of both flights are unknown):
First incident: An Air France Airbus A340-300, registration F-GLZL performing flight AF-279 from Tokyo Narita (Japan) to Paris Charles de Gaulle (France), was enroute at FL310, when the airplane went through a line of thunderstorms. The captain's air speed indication suddenly dropped to 140 knots, the systems issued an alert regarding disagreeing speeds (NAV IAS DISCREPANCY), the navigation display showed a tail wind component of 250 knots. The captain released control of the airplane to the first officer and tried to switch his display from ADIRU1 to ADIRU3. 2 minutes later autopilot and autothrust disconnected and the fly by wire changed into alternate law. The crew noticed icing conditions (static air temperature [SAT] -29 degrees Centigrade) and switched anti ice including pitot heating systems from automatic to on. The speed indications became normal again and agreed again, the autoflight systems were reengaged and ATC informed of severe icing. ATC reported, that two flights had just passed the location without problems. When the crew attempted to reset and reengage ADIRU 1 two times, the system again brought the message "NAV IAS DISCREPANCY" on both attempts, although the speed data appeared consistent. The crew suspected polluted pitot tubes.
Maintenance found, that the drainage holes of all three pitot tubes had been clogged, rendering it very likely that weather combined with the clogged drainage holes caused the incident. Maintenance had reported more clogged drainage holes on A330 and A340 aircraft in the past to Airbus Industries. Airbus Industries was aware of the problems, changes had already been introduced to the pitot tubes on the A320 family, where similiar problems had occured. A modification of the A330/A340 pitot tubes was already planned by AI.
Second incident: An Air France Airbus A340-300, registration F-GLZN performing a flight from Paris Charles de Gaulle (France) to New York JFK,NY (USA), encountered brief turbulence while enroute. The autoflight systems dropped offline, "NAV IAS DISCREPANCY", "NAV PRED W/S DET FAULT" and stall alerts were repeatedly issued during the following two minutes. The airplane continued to JFK without further incident. A review of the policy of retrofitting pitot tubes was recommended and authorities informed.
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Aerial shot of the oil spill (Photo: FAB):
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By Simon Hradecky, created Friday, Dec 12th 2014 15:17Z, last updated Friday, Dec 12th 2014 15:17ZOn Dec 12th 2014 the French BEA have released a 200MB video showing an animation of the accident sequence stating:
This animation has been developed by the BEA for use by aviation professionals to illustrate information contained in the [final] report.
This animation is not intended to be considered as a realistic reconstruction of the event, but has been made in order to ease the understanding of the event.
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By Simon Hradecky, created Thursday, Jul 5th 2012 14:57Z, last updated Thursday, Jul 5th 2012 17:15ZThe French Bureau d’Enquetes et d’Analyses (BEA) released their final report concluding the causes of the crash were:
The obstruction of the Pitot probes by ice crystals during cruise was a phenomenon that was known but misunderstood by the aviation community at the time of the accident. From an operational perspective, the total loss of airspeed information that resulted from this was a failure that was classified in the safety model. After initial reactions that depend upon basic airmanship, it was expected that it would be rapidly diagnosed by pilots and managed where necessary by precautionary measures on the pitch attitude and the thrust, as indicated in the associated procedure.
The occurrence of the failure in the context of flight in cruise completely surprised the pilots of flight AF 447. The apparent difficulties with aeroplane handling at high altitude in turbulence led to excessive handling inputs in roll and a sharp nose-up input by the PF. The destabilisation that resulted from the climbing flight path and the evolution in the pitch attitude and vertical speed was added to the erroneous airspeed indications and ECAM messages, which did not help with the diagnosis.
The crew, progressively becoming de-structured, likely never understood that it was faced with a “simple” loss of three sources of airspeed information. In the minute that followed the autopilot disconnection, the failure of the attempts to understand the situation and the de-structuring of crew cooperation fed on each other until the total loss of cognitive control of the situation. The underlying behavioural hypotheses in classifying the loss of airspeed information as “major” were not validated in the context of this accident. Confirmation of this classification thus supposes additional work on operational feedback that would enable improvements, where required, in crew training, the ergonomics of information supplied to them and the design of procedures.
The aeroplane went into a sustained stall, signalled by the stall warning and strong buffet. Despite these persistent symptoms, the crew never understood that they were stalling and consequently never applied a recovery manoeuvre. The combination of the ergonomics of the warning design, the conditions in which airline pilots are trained and exposed to stalls during their professional training and the process of recurrent training does not generate the expected behaviour in any acceptable reliable way.
In its current form, recognizing the stall warning, even associated with buffet, supposes that the crew accords a minimum level of “legitimacy” to it. This then supposes sufficient previous experience of stalls, a minimum of cognitive availability and understanding of the situation, knowledge of the aeroplane (and its protection modes) and its flight physics. An examination of the current training for airline pilots does not, in general, provide convincing indications of the building and maintenance of the associated skills.
More generally, the double failure of the planned procedural responses shows the limits of the current safety model. When crew action is expected, it is always supposed that they will be capable of initial control of the flight path and of a rapid diagnosis that will allow them to identify the correct entry in the dictionary of procedures. A crew can be faced with an unexpected situation leading to a momentary but profound loss of comprehension. If, in this case, the supposed capacity for initial mastery and then diagnosis is lost, the safety model is then in “common failure mode”. During this event, the initial inability to master the flight path also made it impossible to understand the situation and to access the planned solution.
Thus, the accident resulted from the following succession of events:
- Temporary inconsistency between the airspeed measurements, likely following the obstruction of the Pitot probes by ice crystals that, in particular, caused the autopilot disconnection and the reconfiguration to alternate law;
- Inappropriate control inputs that destabilized the flight path;
- The lack of any link by the crew between the loss of indicated speeds called out and the appropriate procedure;
- The late identification by the PNF of the deviation from the flight path and the insufficient correction applied by the PF;
- The crew not identifying the approach to stall, their lack of immediate response and the exit from the flight envelope;
- The crew’s failure to diagnose the stall situation and consequently a lack of inputs that would have made it possible to recover from it.
These events can be explained by a combination of the following factors:
- The feedback mechanisms on the part of all those involved that made it impossible:
-- To identify the repeated non-application of the loss of airspeed information procedure and to remedy this,
-- To ensure that the risk model for crews in cruise included icing of the Pitot probes and its consequences;
- The absence of any training, at high altitude, in manual aeroplane handling and in the procedure for ”Vol avec IAS douteuse”;
- Task-sharing that was weakened by:
-- Incomprehension of the situation when the autopilot disconnection occurred,
-- Poor management of the startle effect that generated a highly charged emotional factor for the two copilots;
- The lack of a clear display in the cockpit of the airspeed inconsistencies identified by the computers;
- The crew not taking into account the stall warning, which could have been due to:
-- A failure to identify the aural warning, due to low exposure time in training to stall phenomena, stall warnings and buffet,
-- The appearance at the beginning of the event of transient warnings that could be considered as spurious,
-- The absence of any visual information to confirm the approach-to-stall after the loss of the limit speeds,
-- The possible confusion with an overspeed situation in which buffet is also considered as a symptom,
-- Flight Director indications that may led the crew to believe that their actions were appropriate, even though they were not,
-- The difficulty in recognizing and understanding the implications of a reconfiguration in alternate law with no angle of attack protection.
The BEA analysed that the captain appeared unconcerned with regards to the weather ahead as indicated by weather radar ahead at the Intertropical Convergence Zone (ITCZ) and unresponsive to the concerns expressed by the first officer, pilot flying. The BEA said: "He favoured waiting and responding to any turbulence noticed. He vaguely rejected the PF’s suggestion to climb, by mentioning that if “we don’t get out of it at three six, it might be bad”. He certainly meant that if the aeroplane was still in turbulent conditions at FL360, the margins for manoeuvre would be further reduced." and reiterated: "The Captain neither expressed nor explained his position clearly. He seemed to have good experience of the ITCZ, and did not appear personally worried (at worst he expected to be disturbed by the turbulence during his rest). He noticed the turbulence and observed the St. Elmo’s fire. But it seemed that having seen the information available on the radar, he deemed the appearance of the ITCZ crossing to be “normal”. As we do not have the radar image which was provided by his ND, it is difficult to assess the Captain’s appraisal. But the aeroplane had not encountered, before or during the accident, an exceptional meteorological situation from the point of view of phenomena that are traditionally avoided in stormy environments (turbulence, lightning, icing)."
The BEA analysed as result that the radar image probably was not alarming.
The BEA analysed that the time of the captain taking his rest "could be contested, without necessarily calling into question the principle of a relief co-pilot and the trust that this implied in the co-pilots." The choice however was understandable given the ITCZ appeared normal and the second first officer was three times more experienced than the captain. Nonetheless, delaying the rest until the ITCZ would have been crossed would have delayed the rest by only 15 minutes.
The captain did not formally assign the roles to the two first officers. Usually the relief pilot would assume the role of the commander during the absence of the commander from the cockpit. However he did implicitely assign the role of the commander to the first officer in the right hand seat, this distribution of roles containing no ambiguity for the two first officers. This choice however was not free of difficulty: "Indeed, the overall experience and on type of the PF, designated implicitly as relief Captain, was significantly less than that of the PNF, also OCC executive of the airline and as such enjoying recognition as an expert by his peers." The pilot monitoring however then exercised natural authority by recommending, actually asserting, an avoidance strategy for the ITCZ which the pilot flying, relief captain, did not resist to.
The BEA analysed: "Without this leading to the slightest conflict, after the autopilot disconnection, it rapidly led to the inversion of the normal hierarchical structure in the cockpit, with leadership passing to the PNF in the left seat without the role of command being formally and explicitly transferred."
The aircraft subsequently encountered light to moderate turbulence with the autopilot countering the turbulence, the autothrust made a slight reduction of thrust to adjust the cruise mach towards the selected 0.8 mach. A first disturbance in speed caused the autopilot to disconnect with associated aural warning, the speed disturbance probably not noticed by the crew. The crew reacted by reflex with the pilot flying announcing "I have control" and the pilot monitoring acknowledging.
3 seconds later the right hand primary flight display the speed indication dropped from the right hand primary flight display for 5 seconds associated with a drop of altitude by 330 feet, a second later the left hand speed indication became abnormal.
The magnitude of the speed anomaly was "not salient" compared with the autopilot disconnection the crew did not detect a problem with the airspeed indications but with the autopilot disconnection.
No announcements were made with regards to the fly by wire degradation to alternate law and the disconnection of the autothrust system.
The BEA analysed: "For the same reasons relating to salience, it is likely that the crew had not yet perceived the reconfigration to alternate law and the disconnection of the A/THR. It was thus the autopilot disconnection that made the crew aware that there was a problem. The crew, at this time, did not know why the AP had disconnected and the new situation that had suddenly arisen clearly surprised the pilots – a normal reaction for any crew. This degree of surprise can be explained by the contrast between the triggering of a warning and the situation in the cruise phase, during which the pace of change tends to be slow and concentration levels are lower. In addition, the crew’s mental resources were already taken up by turbulence avoidance manoeuvres and the plan to climb during the minutes that preceded the autopilot disconnection. Associated with the environmental conditions (smell of ozone that the PF did not seem to recognise and the noise due to the ice crystals), the PF’s attitude in the minutes that preceded the autopilot disconnection probably constituted a factor that significantly added to the highly charged emotional factors during the sudden and unexpected change in the situation, at night and while passing through the ITCZ, which suddenly confirmed his vague concerns about it. Three seconds after the autopilot disconnection, surprise was a pilot’s natural reaction and cannot be considered as specific to this crew."
The BEA continued analysis: Immediately after detecting the problem an action plan should been developed before taking action. However, after the autopilot disengaged the aircraft rolled from 0 to +8.4 degrees in two seconds without any inputs on the sidestick. The PF was thus immediately absorbed by dealing with the roll.
In addition the PF made abrupt and excessive stick inputs to increase the pitch angle. The BEA analysed: "This nose-up input may initially have been a response to the perception of the aeroplane’s movements (in particular the reduction in pitch angle of 2° associated with the variation in load factor) just before the AP disconnection in turbulence. This response may have been associated with a desire to regain cruise level: the PF may have detected on his PFD the loss of altitude of about 300 ft and loss of vertical speed of the order of 600 ft/min in descent." and continues the abrupt and excessive nature of the input is probably to be explained by the startle effect and emotional shock at the autopilot disconnection "amplified by the lack of practical training for crews in flight at high altitude, together with unusual flight control laws."
The altitude alert (c-chord) began to sound and continued to sound.
The prolonged nature of the nose up inputs however find no explanation, the pilot flying did not verbalize his intentions and the pilot monitoring did not call the pitch angle. It was also not possible to determine what the purpose of the pitch stick input was.
4 seconds after the autopilot disconnected a first stall warning activated due to the rapid increase of the pitch angle and vertical acceleration of the aircraft. The BEA analysed: "it is clear that almost all the crews that heard the stall warning considered it to be surprising and irrelevant. These judgements may be explained by the lack of awareness of the margins in relation to the trigger threshold of the stall warning and by not knowing the triggering conditions of the warning, which are a function of the angle of attack and Mach."
The BEA continued: "It would also seem unlikely that the PNF could have determined the PF’s flight path stabilisation targets. It is worth noting that the inputs applied to a sidestick by one pilot cannot be observed easily by the other one and that the conditions of a night flight in IMC make it more difficult to monitor aeroplane attitudes (pitch attitude in particular). In addition, a short time after the autopilot disconnection, the PF’s statement that he had the controls and his reaction to the initial deviations observed (in particular in roll) may have led the PNF to change his action priorities. Identification of the failure appeared to become a priority over control and flight path monitoring. Consequently, he was unaware of the climb."
3 seconds after the autopilot disconnection the ECAM had no information displayed that would suggest any problem with the indicated airspeeds adding to the confusion, instead the ECAM displayed indication that a maximum speed of 0.82 mach is not to be exceeded (but not stating a minimum speed). "This could lead crews to suppose that the main risk is overspeed. In the absence of any reliable speed indication, this might lead to a protective nose-up input that is more or less instinctive."
About 10 seconds after the autopilot disconnection the crew had built a mental picture of the situation having identified a speed anomaly, however, the crew did not mention how many speed sources they had identified failed. The loss of airspeed indication was almost simultaneously called out by both pilots.
A number of ECAM messages appeared, which "provided no apparent assistance to the crew". The messages identifying different issues did not permit to identify the source of the problems but directed attention in all different directions and were rather confusing than helpful in identifying the problem(s) at hand.
The flight director had been removed from the primary flight displays and now re-appeared with the mode "vertical speed" commanding nose down inputs, the PF inputs were consistent with those flight director indications.
"The PNF detected the climb based on observation and reasoning (“according to all three you’re climbing”), which indicates the beginning of a loss of confidence in the instrument readings. In particular, he asked the PF to stabilise, to pay attention to the airspeed and to descend. His instructions were imprecise insofar as they did not give the PF a firm objective (e.g. maintain altitude or adopt a specific pitch attitude); however, they do appear to have been essential and sufficient for a short-term management of the situation."
The pitch attitude had exceeded 10 degrees nose up, the flight director indications and the PMs calls resulted in the pitch attitude reducing, the aircraft however was still climbing. The flight director began to indicate nose up resulting in the nose down inputs reducing. The PF reduced thrust.
"The PNF had noticed the need to stabilise the flight path, and the need for moderate aeroplane handling inputs. He probably considered that the reduction in pitch and the vertical acceleration sensed was a sufficient sign that the PF would correct the flight path to allow him to devote himself once again to identifying the failure."
The right hand air data #2 were at the verge of becoming reliable again when the pilot monitoring, attempting to resolve the situation, unilaterally decided to switch the air data source to #3 and thus unintentionally prevented the right hand primary flight display air data from becoming valid again.
The c-chord warning was still sounding and had saturated the aural environment in the cockpit which "certainly played a role in altering the crew’s response to the situation". 42 seconds after the autopilot disconnected one of the crew pushed the master caution button, probably due to the fact it had been illuminated since the first stall warning, the c-chord ceased.
The flight director bars re-appeared in vertical speed mode commanding a climb rate of 1400 feet per minute. The mode was never called by the crew. The bars indicated a slight nose up required.
46 seconds after the autopilot disengaged a second stall warning activated consisting of a synthetic voice calling "Stall! Stall!" and a cricket. In addition a visual display of a red and black strip at the speed tape on the primary flight display would normally occur except when the calculation of the stall warning speed was no longer possible, in which case no visual indication would occur.
"The aural characteristics of the warning (a synthetic voice saying “Stall, stall” and the cricket), or the “deterrent buffet” vibrations, are thought to be so intrusive that they will make the crew realise that their understanding of the situation is mistaken, and will call their attention to the fact that the aeroplane is approaching the limits of the flight envelope."
The aircraft still continued to climb with the stick inputs still commanding a nose up when only a nose down input could have brought the aircraft back within the flying envelope. The kinetic energy of the aircraft was converted into potential energy causing a rapid speed reduction, which increase the angle of attack, the resulting drag of the high angle of attack exceeded the thrust available from the engines so that the aircraft could no longer accelerate by thrust from the engines. Inevitably the aircraft began to descend, stick inputs still commanded nose up and the angle of attack increased further as result.
"Subsequently, the position of the sidestick, maintained in its nose-up or neutral position, continued to exacerbate the situation and made the recovery uncertain, even impossible."
The BEA analysed: "The crew never referred either to the stall warning or the buffet that they had likely felt. This prompts the question of whether the two co-pilots were aware that the aeroplane was in a stall situation. In fact the situation, with a high workload and multiple visual prompts, corresponds to a threshold in terms of being able to take into account an unusual aural warning. In an aural environment that was already saturated by the C-chord warning, the possibility that the crew did not identify the stall warning cannot be ruled out. ... Finally, although the PNF had called out the reconfiguration to alternate law when reading the ECAM, and even though the indicators of the loss of protection should have been displayed on the PFD (SPD LIM and an amber cross in roll and yaw), it is possible that the PF was not fully aware of this reconfiguration and of what it implied. He may therefore have embraced the common belief that the aeroplane could not stall, and in this context a stall warning was inconsistent."
When the captain returned to the cockpit he had certainly heard the stall warning and noticed the vibrations linked to buffet and the pitch attitude of 15 degrees, however made no reference to this. The aircraft was in a rapid descent close to the originally assigned altitude at that point. The stall warning became intermittent and interwoven with the altitude alert (c-chord). Both warnings combined created a saturated aural environment. The captain had difficulty to understand what the first officers were saying and while trying to read the instruments, faced with the description the first officers had lost control and had tried everything without a more precise decription of the sequence of events, he would have needed to query the first officers about the sequence of events, which was however impossible due the urgency of the situation and the stress conveyed by the first officers, he had difficulty to diagnose the situation. His interventions made clear that he too had not understood the aircraft was stalling.
Descending through FL315 the angle of attack had stabilized around 40 degrees nose up. "Only an extremely purposeful crew with a good comprehension of the situation could have carried out a manoeuvre that would have made it possible to perhaps recover control of the aeroplane. In fact, the crew had almost completely lost control of the situation."
The BEA analysed with regards to pilot training and flight simulator "demonstrations" of stall during their initial training for the type rating, that those two opportunities to learn about an approach to stall with fly by wire at normal and alternate law were conducted at low altitude (FL100). "At high altitude, the margin between the normal angle of attack in cruise and the angle of attack that activates the stall warning is very small. Trainees who perform the exercise at low altitude note a reduction in speed compared with the reference values but are not sensitized to the proximity of the angle-of-attack threshold at which the warning is triggered. The demonstrative nature of the exercises undertaken does not enable the crew to appreciate the startle effect generated by the stall warning, nor the reflex actions on the controls that may be induced."
The BEA goes on to condemn training philosophies in their analysis: "Current training practices do not fill the gap left by the non-existence of manual flying at high altitude, or the lack of experience on conventional aeroplanes. Furthermore, they limit the pilots’ abilities to acquire or maintain basic airmanship skills."
The BEA analysed that usually airliners are designed to provide for a positive longitudinal static stability meaning, the aircraft would return to its point of equilibrium (trim) with the controls neutral. This however is not true for the A330 which has a neutral longitudinal static stability meaning, that in alternate law with the aircraft approaching to stall neutral stick inputs would not prevent the aircraft from stalling demanding active nose down inputs for recovery.
The BEA continues: "When there are no protections left, the aeroplane no longer possesses positive longitudinal static stability even on approach to stall. This absence specifically results in the fact that it is not necessary to make or increase a nose-up input to compensate for a loss of speed while maintaining aeroplane altitude. This behaviour, even if it may appear contrary to some provisions in the basic regulations, was judged to be acceptable by the certification authorities by taking into account special conditions and interpretation material. Indeed, the presence of flight envelope protections makes neutral longitudinal static stability acceptable."
The flight directors, other than the autoflight systems which disconnected automatically, did not disconnect, but were removed from display. The unreliable airspeed procedures require the flight directors to be disengaged with the intention to avoid conflicting and false flight director indications. With the flight directors not being disengaged, the display of the flight directors would resume as soon as the operating conditions were regained.
This behaviour of the flight directors probably played a role into the accident as combination of following factors:
"- credibility of the cross bars is strengthened by their disappearance followed by their re-appearance: if they appear, it implies that the indications that they display are valid;
- Since they attract the crew’s attention (green colour and presentation in the centre of the PFD), the presence of the cross bars could have influenced the actions of the PF, notably in respect to his reaction to the stall warning;
- It is only possible to be aware of the changes in active modes (when the cross bars reappear) by reading the FMA, which is probably difficult to do in a high workload situation induced by piloting or failure management tasks."
The BEA reported that stall warnings are a frequent occurrence in zones of turbulence and thus led crews to discard the stall warnings as "spurious" (nuisance). "For this reason, the behaviour of the AF 447’s crew should be considered as liable to be reproduced as regards the lack of reaction to the first STALL warning."
In addition, the flight crew manual released by the aircraft manufacturer states that a stall warning in alternate or direct law is identified by the combination of the aural warning, the illumination of the master caution AND the red and black stripe on the airspeed tape. The FCOM makes no mention of buffeting and does not take into account the loss of computation of the stall warning speed, which prevents the display of the red and black stripe. In the absence of the stall warning speed only the aural warning is therefore unambiguous.
Thus the BEA analysed: "The salience of an aural warning not reiterated visually in symbolic form, on a very “visual” aeroplane, is doubtless insufficient. However, irrespective of the ergonomics of the warning, it is likely that the presentation of information that provides an overview of the aeroplane’s situation (angle of attack, energy balance (kinetic and potential), flight envelope) would help pilots to “make sense” of the warning and to take the appropriate corrective action in time."
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By Simon Hradecky, created Thursday, Jul 5th 2012 12:36Z, last updated Thursday, Jul 5th 2012 14:39ZThe French BEA is just holding the press conference to release the final report into the crash of the flight, this coverage was updated as soon as important statements are being made and is now complete. The summary of final report will be summarized as soon as the report has been released a few hours after 16:30L (14:30Z) and has been processed as usual.
The aircraft had been flying normally crossing Natal with the captain being pilot monitoring and the first officer being pilot flying. The second first officer was taking his rest. The captain was not worried about the forecast weather conditions along the route, and while over the Atlantic left the cockpit for his rest period with the second first officer taking the left hand seat. There was no briefing, especially not with regards to the Intertropical Convergence Zone. After the captain left the cockpit the two first officers discussed the echos visible on the weather radar.
Ice crystals blocked the dynamic ports of the pitot probes, the autopilot disconnected and the altitude warning sounded, the aircraft climbed up to 38,000 feet with up to more than 6000 feet per minute climb rate. The fly by wire system degraded from normal law.
The stall warning activated, several signals were sent to the captain by the pilot not flying (second first officer), the aircraft entered "pronounced stall" and the aircraft started to descend at more than 7000 feet per minute with an angle of attack of more than 40 degrees.
Just when the captain entered the cockpit the stall warning ceased and re-occurred, the AoA was between 35 and 40 degrees and the vertical rate of descent between 11000 and 15000 feet per minute until impact with the water.
The starting point was the formation of icy crystals which disrupted the air flow and pressure measured by the dynamic ports of the pitot tubes leading to airspeed inconsistencies and the disconnection of the autopilot and autothrust system. The pilot flying is supposed to take control manually monitoring the systems, detecting the airspeed inconsistencies and maintain a proper pitch attitude and thrust setting.
Instead of keeping the pitch at a maximum of 6 degrees, at which the aircraft would stall at high altitude, the pilot flying pitched up beyond that angle. The crew did not follow standard operating procedures.
The pilot not flying did not detect the deviation from the flight trajctory and speeds and did not call the deviations. The lack of such interventions led the pilot flying to take actions that did not reduce the pitch angle.
The flight directors provided indications to increase the nose up attitude.
The aircraft subsequently departed its flight envelope, the control stick remained in the nose up position.
The crew never referred to the stall alarm and the buffeting that occured. The crew never understood they were stalling.
The captain came back into the cockpit certainly having heard the stall warning and certainly having felt the strong vibrations caused by the buffets but also did NOT identify the aircraft was stalling.
The absence of training in manual handling of the aircraft at high altitude, especially also with regards to unreliable airspeeds can explain the reaction of the crew, also the trained procedure related to airspeed anomalies misled the crew to false required pitch angles.
25 safety recommendations were made with regards to pilot training, knowledge of systems especially in degraded modes, manual handling training, knowledge of flight dynamics. Safety recommendations were also made into the topic of flight director indications, stall warnings, and mode changes. On approach to stall a dedicated visual indication in addition to the aural announcements has been recommended.
Safety recommendations have also been made to search and rescue operations.
8 safety recommendation concern pilot training, 8 safety recommendations concern aircraft certification.
The accident is categorized as loss of control as result of loss of situational awareness.
The automated systems have improved safety substantially in the last years, however, as soon as the automated systems disconnect flight crew are increasingly unable to comprehend the resulting scenario. Information presented to the pilots as well as the cognitive capabilities of humans are in the focus of attention in this regard.
This concluded the factual presentation by the BEA, now the conference has entered the question and answer part.
In the last few seconds of the descent the aircraft had entered deep stall during which recovery was next to impossible except to specially trained to crew, no pilot could have recovered from this final stall. The aircraft should never have been allowed to leave the flight envelope and come into a situation of a developed stall, not to mention a deep stall.
The Airbus family of aircraft has never been put through stall recovery during certification opposite to the Boeing 787. The Boeing test crew flying the stall were surprised by the very different sounds associated with the stall of the aircraft in comparism to a Cessna.
In an intensive stress scenario the humans blank out aural signals first. Every military pilot, every test pilot knows that in intense stress situations aural alerts are not being heard.
Goodrich probes are not immune to icing as well, however, far fewer events have been registed with these probes.
At the start of the event the altitude indication dropped by 400 feet as result of the loss of Mach number due to the computed corrections, the loss of 400 feet of altitude has further provided incentive to increase the pitch angle.
Had the pilots done nothing after the autoflight systems disconnected it is difficult to know/estimate whether the accident would have happened or not. It is true however that in a number of other events the aircraft maintained its general flight envelope with the crew doing nothing following autoflight system disconnection.
There is no proof that the crew followed flight director indications. The green bars however are very attractive, pilots are used to continue what they do normally, and it is not implausible that the crew did follow the green bars of the flight director.
The flight director indications were not recorded by the flight data recorders, but were recomputed following the preliminary report #3, these computations and knowledge resulted thereof are a new element beyond report #3.
The false data off the air data computers following the obstruction of the pitot probes by ice crystals resulting in false instrument readings as well as the immediate actions by the crew created confusion making it impossible for the crew to determine what flight status they were in.
The obstruction of the pitot probes triggered the sequence of events, the subsequent actions by the crew de-stabilized the aircraft trjactory and led the aircraft to leave its flying envelope.
The pilot actions can be explained by the crew being afraid of getting into an overspeed scenario mainly also due to the noises that occurred at the flight deck. As a result the crew never realised they were stalling.
The 25 safety recommendations in the final report add to the 16 safety recommendations issued so far in the preliminary reports.
During the final 4 minutes of flight the flight directors disappeared and reappeared multiple times, the modes changed. The flight director indications did not provide for a recovery of the aircraft, however, at the initial stages of the aircraft leaving its assigned trajectory and approaching the boundaries of its flying envelope it was possible to recover the aircraft. As the crew never realized they were stalling they were never able to disregard the flight director and take the appropriate actions to lower the nose. Appropriate action to lower the nose and the flight director indications were inconsistent. The flight director indications would need to be taken in the context of the active mode indicated in the according announciators. The flight directors were NOT disengaged as they SHOULD have been. The modus of flight director operation is being further looked into.
There had been other similiar occurrences during which the altitude was maintained within +/- 500 feet. It is not possible to state, whether another crew could have kept the aircraft within its flying envelope or not, it is impossible to tell whether the accident would have happened with another crew at the controls or not. It is likely however that the accident would have happened to other crews as well.
A test flight verified that the stall buffeting was perceived at the pilot seats, bringing the nose down would have quickly returned (recovered) the aircraft into the flying envelope.
It is true that in FBW normal law it is not necessary to train pilots for a stall situation, and it is true that pilots are not really trained for stall scenarios.
The certification bodies have reviewed the unreliable airspeed procedures at high altitude and confirmed that maintaining a pitch angle of 5 degrees nose up would have provided time to sort out the unreliable airspeed and would have kept the aircraft flying.
This concluded the press conference. The final report is to be released in the next few hours.
From this editor's point of view a short personal summary of the scenario that the BEA investigators painted in the press conference:
Following the disconnection of the autoflight systems as result of the pitot probes being obstructed and airspeeds marked unreliable, the crew went into serious stress levels while trying to figure out what the situation was. The flight director, initially in altitude hold mode, indicated nose down and thus helped a temporary recovery of the aircraft, but disconnected and re-connected in a different mode now demanding a pitch up attitude. The crew, still uncertain about what the situation was and fearing they were going into overspeed, likely took this nose up indication as affirmation of their belief they were in an overspeed scenario and therefore continued to provide nose up inputs not hearing the aural stall warnings as result of stress level induced blank out of information and mistaking the stall buffeting as overspeed buffeting.
In addition, the crew had been trained to adopt a 10-15 degrees nose up attitude in unreliable airspeed procedures, which was true and correct for low altitude, however, not at high altitude where this procedure would lead the aircraft to leave its flying envelope and depart controlled flight with stall occurring at angle of attacks of just above 4 degrees. Certifying authorities reviewed that procedure and found, that adopting a 5 degrees nose up pitch would get the aircraft into a gradual climb and keep it flying thus providing for sufficient time to analyse and work out what situation had occurred and how to deal with the scenario.
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By Simon Hradecky, created Friday, Jul 29th 2011 16:35Z, last updated Thursday, Jul 5th 2012 17:18ZThe BEA have released their third preliminary report in French, on Aug 4th 2011 the BEA released their English translation.
While it doesn't appear there have been additions to the factual part already released in report #2, report number #3 contains first analysis of the crash.
In there the BEA reported, that the aircraft departed Rio de Janeiro with the captain in the left hand seat, the first first officer in the right hand seat and the second first officer in the observer seat.
At 01:55Z the captain left his seat in order to take his rest, the second first officer took the captain's seat. The first first officer (in the right hand seat) became pilot flying (PF), the second first officer pilot monitoring (PNF).
The captain was observing the briefing the two first officers conducted. The PF pointed out there was a little bit of turbulence ahead according to weather radar's image but they couldn't climb, pointing out the FMS indication of maximum possible cruise level of 375. Subsequently the captain left without leaving any instructions with the first officers, especially not assigning tasks. This absence of formal framework later led to a breakdown of optimal crew cooperation between the two first officers.
The turbulence increased, at 02:08Z the PF decided to turn left by 12 degrees selecting heading mode into the autopilot. The PF remarked he would prefer to climb to FL360. Intensive weather radar observations followed however were interrupted by a sensation of quick temperature increase and the appearance of an odour that distracted the crew for more than a minute. The PNF finally identified the smell as ozone.
Discussions in the cockpit did not suggest any malfunctions.
At 02:09:46Z the background noise on the cockpit voice recorder significantly changed, the BEA analysed the sound was consistent with the characteristics of presence of ice crystals, the change in sounds getting the attention of the first officers who had not experienced this before. The PNF takes action and suggests to slow down to Mach 0.8 and engages engine anti-ice on.
At 02:10:05Z a sharp drop of airspeed indications occurred likely due to obstruction of the pitot probes by ice crystals. The autopilot and autothrust systems disengaged as result. The presence of turbulence led to the aircraft rolling right to a bank angle of 8 degrees, the nose pitches up to 11 degrees nose up within 10 seconds. The PF announces "I have control" and makes a quick left nose up input almost to the mechanical stops of the side stick. The nose pitches further up and at 02:10:10Z the stall warning activates.
Between 02:10:18Z and 02:10:25Z the PNF reads various ECAM messages, then attracts the attention of the PF to the loss of speed. At that time both left hand and ISIS airspeeds were below 100 knots, the aircraft was climbing by 7000 feet/min and the aircraft rolls left and right, with the bank angle remaining between -10 and +10 degrees of bank, as result of PF inputs. Both first officer recognized the loss of airspeed indications, however none called for the unreliable airspeed procedures. Comparing the three airspeed indications the PNF urges the PF multiple times to lower the nose. The aircraft was climbing through FL370 and continued to climb.
At 02:10:34Z the left airspeed sharply rose to 215 KIAS and became valid again, the speed indication of the stand by instrument (ISIS) remained wrong. The BEA analysed that the loss of speed was 60 knots from the point of autopilot disengaging until that time, the 60 knots loss of speed being consistent with the aircraft climbing 2000 feet in that configuration.
At 02:10:47Z the thrust levers were moved to about 2/3 of travel resulting in 85% N1. The climb rate reduced to 100 feet/min, the angle of attack reduced to about 3 degrees and the roll is controlled. The first officers now attempt to call the captain back to the cockpit. The BEA analyses that after a quick trim and levelling off as result of PF inputs the trajectory of the aircraft appeared controlled again, however the initial increase in altitude was excessive and should have been pointed out by the PNF. However, none of the pilots called out speeds, vertical speeds, pitch angles or altitude.
At 02:10:51Z the stall warning activated again, the pitch angle had increased to about 6 degrees nose up. As result of PF inputs the pitch angle increased from 6 to 13 degrees and the angle of attack increased to 10 degrees. Rapid onset of buffeting occurred. 5 seconds later the thrust levers are placed into the TOGA detent. The BEA analysed that was about the point where the aircraft went out of control.
The PF maintains inputs to keep the nose up between 11 and 23 degrees nose up with the angle of attack being betwen +11 and +18 degrees.
At 02:11:07Z the ISIS airspeed becomes valid at 183 KIAS, and all three indicated airspeeds agree. The PF selected ADR3 as input for his primary flight display. The vertical speed drops through 0 and becomes highly negative (around 4000 feet/minute sink rate), the airspeed reduces further to 160 KIAS.
At 02:11:20Z the PF states twice he has lost control of the aircraft.
At 02:11:37Z the PNF pushes the priority button and provides a large left input in reaction to a high right bank, calling "controls on the left". He almost instantly released the priority button and ceased control inputs again without required calls.
At 02:11:42Z the captain entered the cockpit, just before the stall warning stops, the airplane was at 35800 feet MSL, 9100 feet/min sink rate, airspeeds below 100 KIAS, pitch 12 degrees nose up and engines at 102% N1. Neither first officer provides an account to the captain what is happening. The BEA analysed that when the stall warning stopped all three AoA computations had become invalid due to too low an airspeed. Airspeeds are no longer displayed on both PFDs.
At 02:12:04Z the PF remarked he believed they were in overspeed, the BEA assumes because of the excessive background noise in the cockpit. None of the two other pilots supported that hypothesis which was in contradiction to instrument indications, high pitch angle and high rate of descent.
Until impact now the stall warning activates when the nose is lowered and silences when the pitch angle increases. FDR data suggest that as soon as the stall warning activates the pilots react with nose up inputs which cause the stall warning to silence again.
The BEA analysed that none of the three pilots ever worked out which indications to trust and which not.
The BEA analysed that both first officers had been trained unreliable airspeed emergency maneouvers at low altitude which required them to disengage flight directors and autoflight systems, then adopt an attitude between 10 and 15 degrees nose up. At altitude however the stall warning would activate at an angle of attack just above +4 degrees.
The BEA listed following findings:
- The Captain’s departure occurred without clear operational instructions
- The crew composition was in accordance with the operator’s procedures
- There was no explicit task-sharing between the two copilots
- The weight and balance of the airplane were within operational limits
- The crew had noticed returns on the weather radar
- The crew made a heading change of 12° to the left of its route
- The AP disconnected while the airplane was flying at upper limit of a slightly turbulent cloud layer
- There was an inconsistency between the measured speeds, likely as a result of the obstruction of the Pitot probes in an ice crystal environment
- At the time of the autopilot disconnection, the Captain was resting
- Even though they identified and announced the loss of the speed indications, neither of the two copilots called the procedure "Unreliable IAS"
- The copilots had received no high altitude training for the "Unreliable IAS" procedure and manual aircraft handling
- No standard callouts regarding the differences in pitch attitude and vertical speed were made
- There is no CRM training for a crew made up of two copilots in a situation with a relief Captain
- The speed displayed on the left PFD remained invalid for 29 seconds
- The approach to stall was characterised by the triggering of the warning, then the appearance of buffet
- A short time after the triggering of the stall warning, the PF applied TO/GA thrust and made a nose-up input
- In less than one minute after the disconnection of the autopilot, the airplane was outside its flight envelope following the manual inputs that were mainly nose-up
- Until the airplane was outside its flight envelope, the airplane’s longitudinal movements were consistent with the position of the flight control surfaces
- Neither of the pilots made any reference to the stall warning
- Neither of the pilots formally identified the stall situation
- The invalidity of the speed displayed on the ISIS lasted 54 seconds
- The Captain came back into the cockpit about 1 min 30 after the autopilot disconnection
- The angle of attack is the parameter that enables the stall warning to be triggered; if the angle of attack values become invalid, the stall warning stops
- By design, when the speed measurements were lower than 60 kts, the 3 angle of attack values became invalid
- Each time the stall warning was triggered, the angle of attack exceeded its theoretical trigger value
- The stall warning was triggered continuously for 54 seconds
- The airplane’s angle of attack was not directly displayed to the pilots
- Throughout the flight, the movements of the elevator and the THS were consistent with the pilot’s inputs
- The engines were working and always responded to the crew’s inputs
- No announcement was made to the passengers
Air France commented: "It should be noted that the misleading stopping and starting of the stall warning alarm, contradicting the actual state of the aircraft, greatly contributed to the crew’s difficulty in analyzing the situation. During this time, the crew, comprising both First Officers and the Captain, showed an unfailing professional attitude, remaining committed to their task to the very end. Air France pays tribute to the courage and determination they showed in such extreme conditions. At this stage, there is no reason to question the crew’s technical skills."
The French BEA released new safety recommendations mainly recommending to introduce an AoA indication on the cockpit instruments, introducing additional training for manual aircraft control at altitude, additional definitions for the role of a relief captain to ensure proper task sharing in the cockpit as well as recommendations regarding flight data recorders.
Translated Transcript (PIC: Captain, PF: Pilot Flying, PNF: Pilot monitoring):
| Time | Source | |
|---|
| 02:00:33 | PF | Well a bt of turbulence which you just saw… we will … we should find it again before, in fact we are in the cloud layer unfortunately as we can not climb too much for the moment because of the temperatue which is sinking less than expected. This is reducing the REC MAX for us a little lower to go for 37 (FL370) | | 02:06:44 | PF | The ITC, there it is between SALPU and TASIL | | 02:06:54 | PF | Minus 42, we are not going to use the anti ice it is still there | | 02:07 | PF | You see we are really on the limit of the cloud layer. | | 02:08:07 | PNF | Can you maybe turn a bit to the left? I agree that we are in manual, right? | | 02:08:19 | PNF | What I call manual means we are not in managed mode (Nav) | | 02:09:54 | PNF | Here, I’ll reduce the speed a bit for you. | | 02:10:03 | PF | Do you want to switch to Ignition Start? | | 02:10:06 | PF | I have control | | 02:10:09 | PF | Ignition Start | | 02:10:11 | PNF | What is this? | | 02:10:14 | PF | We don’t have a good… We don’t have a good indication of …. | | 02:10:17 | PNF | We have lost the speeds, engine thrust A T H R engine lever thrust | | 02:10:18 | PF | … speed | | 02:10:22 | PNF | Alternate Law Protections | | 02:10:24 | PNF | Wait, we are about to loose | | 02:10:25 | PNF | Wing Anti-Ice | | 02:10:27 | PNF | Watch your speed, Watch your speed | | | PF | Ok, ok, I will descend back | | | PNF | You are stabilizing | | | PF | Yeah | | | PNF | You are descending back | | 02:10:33 | PNF | According to the three you are climbing, now you are descending. | | 02:10:35 | PF | Agreed | | 02:10:36 | PNF | You are at… descend back | | | PF | It is going, we are descending back | | 02:10:39 | PNF | I’ll put you on A T T (*) (Selecteur ATT /HDG is put in position F/O on 3) | | 02:10:42 | PF | We are, yes we are in climb | | 02:10:49 | PNF | Where is he, eh? | | 02:10:56 | PF | TOGA | | 02:11 | PNF | Try to use the lateral controls as few as possible hey! | | 02:11:03 | PF | I am in TOGA | | 02:11:06 | PNF | … is he coming or not | | 02:11:21 | PNF | We have certainly the engines, what is happening? | | 02:11:32 | PF | I don’t have control of the aircraft, I don’t have control of the aircraft at all | | 02:11:38 | PNF | Command to the left (taking control) | | 02:11:41 | PF | I have the impression that we have speed…. (we are in speed) | | 02:11:43 | PIC | Hey, what are you doing? | | | PNF | What is happening, I don’t know, I don’t know what is happening | | 02:11:53 | PIC | Ok, take, take this | | 02:11:58 | PF | have a problem, I have no more vertical speed here | | | PIC | Agreed | | | PF | I have no indication at all. | | 02:12:04 | PF | I have the impression that we have a crazy speed, no, what do you think? | | | | [Speedbrakes are deployed] | | 02:12:07 | PNF | NO, don’t extend them! Certainly not. | | 02:12:13 | PNF | What do you think, what doyou think, what do we have to do? | | 02:12:15 | PIC | I don’t know, it descends. | | 02:12:10 | PF | Here, that is good, we have wings level, no it doesn’t want. | | | PIC | Wings to level, the horizon, the backup horizon. | | | PNF | The horizon (secondary) | | 02:12:26 | PNF | The speed? | | 02:12:27 | PNF | You are climbing, | | | VS | Stall Stall | | | PNF | You are descending, descending descending | | 02:12:30 | PF | I am descending? | | | PNF | Descend! | | 02:12:32 | PIC | No, you are climbing | | 02:12:33 | PF | Here, I am climbing, okay, right so lets descend (or okay we are descending) (unclear) | | 02:12:42 | PF | OK, we are in TOGA | | 02:12:42 | PF | On the altitude where are we? | | 02:12:44 | PIC | this is not possible | | 02:12:45 | PF | On alti(tude) we are where? | | 02:12:45 | PNF | What do you mean on altitude? | | | PF | Yes, yes, yes, I am descending there, no? | | | PNF | Yes, you are descending. | | | PIC | Hey, you are in…. put the wings level, | | | PNF | Put the wings level! | | | PF | That is what I am trying to do | | | PIC | Put the wings level | | 02:12:59 | PF | I am at the limit of, with the warping | | | PIC | The rudder | | 02:13:25 | PF | What, how is it that we are continuing to descend at the limit there? | | 02:13:28 | PNF | Try to find what you can do with the controls up there, The primaries e.t.c. | | 02:13:32 | PF | At level 100 | | 02:13:36 | PF | 9000 ft | | 02:13:38 | PIC | Carefull with the rudder! | | 02:13:39 | PNF | Climb, climb. Climb, climb | | 02:13:40 | PF | But I am at the limit of the nose since a while | | | PIC | No, no, no, don’t climb | | | PNF | So descend | | 02:13:45 | PNF | So, give me the controls, to me the controls. | | | PF | Go ahead, you have the controls, we are still on TOGA | | 02:14:05 | PIC | Careful, you are nose high (cabres? ) | | | PNF | I am nose high? | | | PF | Well, we need to, we are at 4000 ft | | 02:14:18 | PIC | Go, Pull | | | PF | Go, Pull pullpull | | 02:14:26 | PIC | Ten degrees pitch |
Editorial note: at 02:12:04Z the transcript mentions the speedbrakes have been deployed, the FDR graphics as well as the remainder of the report do not mention at all whether the speedbrakes have been extended or not.
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By Simon Hradecky, created Friday, Jul 29th 2011 11:08Z, last updated Friday, Jul 29th 2011 15:22ZThe French BEA have released an executive summary of the additions to the second preliminary report. Around 17:20L (15:20Z) the third preliminary report in French has been released.
The French BEA also released new safety recommendations mainly recommending to introduce an AoA indication on the cockpit instruments, introducing additional training for manual aircraft control at altitude, additional definitions for the role of a relief captain to ensure proper task sharing in the cockpit as well as recommendations regarding flight data recorders.
Air France issued a press release in direct response to the BEA's executive summary stating: "It should be noted that the misleading stopping and starting of the stall warning alarm, contradicting the actual state of the aircraft, greatly contributed to the crew’s difficulty in analyzing the situation. During this time, the crew, comprising both First Officers and the Captain, showed an unfailing professional attitude, remaining committed to their task to the very end. Air France pays tribute to the courage and determination they showed in such extreme conditions. At this stage, there is no reason to question the crew’s technical skills."
The executive summary does not provide new details over preliminary report number 2 however lists a number of BEA findings:
- The Captain’s departure occurred without clear operational instructions
- The crew composition was in accordance with the operator’s procedures
- There was no explicit task-sharing between the two copilots
- The weight and balance of the airplane were within operational limits
- The crew had noticed returns on the weather radar
- The crew made a heading change of 12° to the left of its route
- The AP disconnected while the airplane was flying at upper limit of a slightly turbulent cloud layer
- There was an inconsistency between the measured speeds, likely as a result of the obstruction of the Pitot probes in an ice crystal environment
- At the time of the autopilot disconnection, the Captain was resting
- Even though they identified and announced the loss of the speed indications, neither of the two copilots called the procedure "Unreliable IAS"
- The copilots had received no high altitude training for the "Unreliable IAS" procedure and manual aircraft handling
- No standard callouts regarding the differences in pitch attitude and vertical speed were made
- There is no CRM training for a crew made up of two copilots in a situation with a relief Captain
- The speed displayed on the left PFD remained invalid for 29 seconds
- The approach to stall was characterised by the triggering of the warning, then the appearance of buffet
- A short time after the triggering of the stall warning, the PF applied TO/GA thrust and made a nose-up input
- In less than one minute after the disconnection of the autopilot, the airplane was outside its flight envelope following the manual inputs that were mainly nose-up
- Until the airplane was outside its flight envelope, the airplane’s longitudinal movements were consistent with the position of the flight control surfaces
- Neither of the pilots made any reference to the stall warning
- Neither of the pilots formally identified the stall situation
- The invalidity of the speed displayed on the ISIS lasted 54 seconds
- The Captain came back into the cockpit about 1 min 30 after the autopilot disconnection
- The angle of attack is the parameter that enables the stall warning to be triggered; if the angle of attack values become invalid, the stall warning stops
- By design, when the speed measurements were lower than 60 kts, the 3 angle of attack values became invalid
- Each time the stall warning was triggered, the angle of attack exceeded its theoretical trigger value
- The stall warning was triggered continuously for 54 seconds
- The airplane’s angle of attack was not directly displayed to the pilots
- Throughout the flight, the movements of the elevator and the THS were consistent with the pilot’s inputs
- The engines were working and always responded to the crew’s inputs
- No announcement was made to the passengers
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By Simon Hradecky, created Friday, May 27th 2011 12:52Z, last updated Friday, May 27th 2011 12:52ZThe French BEA release an interim narration of newly discovered facts following the read out of the black boxes stating, that the captain had left his seat about 15 minutes prior to the last position report handing control of the aircraft to the first officer and the second officer, who were occupying the left and right hand seats and were flying at the time of the accident. The captain attended the briefing of the two officers about 11-9 minutes prior to the last position report (at 02:10Z), the pilot flying stated: "the little bit of turbulence that you just saw […] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much for the moment because the temperature is falling more slowly than forecast" continuing "the logon with Dakar failed". After the briefing the captain left the cockpit.
The airplane was flying at FL350 at Mach 0.82 at that time, weight was about 205 tons and the center of gravity was at 29%, well within limits.
At 02:06Z the pilot flying called the cabin informing cabin crew: "in two minutes we should enter an area where it’ll move about a bit more than at the moment, you should watch out". At 02:08Z the pilot not flying suggested "you can maybe go a little to the left […]", the airplane entered a slight left turn turning off the course by about 12 degrees. Levels of turbulence increased and the crew slowed to 0.8 mach in response.
At 02:10:05Z the autopilot followed by autothrust disengaged (and remained disengaged until impact), the pilot flying said "I have controls", the airplane began to turn right and the pilot made a left nose up input. The stall warning sounded twice in a row. The recorded parameters show a sharp decrease of airspeed from about 275 knots to 60 knots indicated airspeed displayed in the left hand primary display followed by a similiar indication in the stand by instruments (the right hand speed indications are not recorded by the FDR).
At 02:10:16Z the pilot monitoring said "so, we’ve lost the speeds" followed by "alternate law […]".
The airplane's angle of attack progressively increased above 10 degrees nose up and the airplane started to climb reaching up to 7000 feet per minute of climb rate. The pilot flying made nose down inputs followed by left and right roll commands, the climb rate reduced to 700 feet per minute, the bank angles varied between 10 degrees left and 12 degrees right. The speed indication on the left primary instrument sharply increased to 215 KIAS (Mach 0.68), the airplane reached FL375, the angle of attack reduced to 4 degrees.
At 02:10:50Z the pilot monitoring repeatedly attempted to call the captain back into the cockpit.
At 02:10:51Z the stall warning sounded again. The thrust levers were placed into the TO/GA detent, and the pilot flying made nose up commands on his side stick. The angle of attack increased again through 6 degrees nose up and continued to increase, the trim went from 3 degrees to 13 degrees nose up in about one minute and remained there until impact.
About 15 seconds after the second stall warning the airspeed indicated on the standby instruments sharply increased to 185 KIAS and became consistent with the left hand speed. The pilot flying continued to make nose up inputs, the airplane reached FL380, pitch and angle of attack reached 16 degrees nose up.
At 02:11:40Z the captain entered the cockpit, at that time the indicated airspeeds became invalid (airspeeds are removed being considered invalid below 30 knots, AoA values are considered invalid below 60 KIAS) and the stall warning stopped.
The airplane at that point was at FL350, pitch did not exceed 15 degrees nose up, the angle of attack exceeded 40 degrees nose up and the descent rate had reached 10,000 feet per minute. The airplane encountered roll oscillations of up to 40 degrees of bank angles, the pilot flying made a control input to the full left and full nose up, that lasted for 30 seconds. Both co-pilots stated they had no (valid) indications.
At 02:12:02Z the thrust levers were placed into idle, the pilot flying made nose down inputs, the angle of attack reduced and the indicated airspeeds became valid again.
At 02:13:32Z the pilot flying remarked "we are going to arrive at flight level 100". About 15 seconds later inputs were recorded from both side sticks, the pilot flying said "go ahead you have the controls".
The angle of attack remained above 35 degrees nose up.
The recordings stopped at 02:14:28Z, the last recorded values were: "10,912 feet/min descent rate, ground speed of 107 knots, pitch angle 16.2 degrees nose up, bank angle 5.3 degrees left and a magnetic heading of 270 degrees.
The BEA summarised the new findings:
- The composition of the crew was in accordance with the operator’s procedures.
- At the time of the event, the weight and balance of the airplane were within the operational limits.
- At the time of the event, the two co-pilots were seated in the cockpit and the Captain was resting. The latter returned to the cockpit about 1 min 30 after the disengagement of the autopilot.
- There was an inconsistency between the speeds displayed on the left side and the integrated standby instrument system (ISIS). This lasted for less than one minute.
- After the autopilot disengagement:
* the airplane climbed to 38,000 ft,
* the stall warning was triggered and the airplane stalled,
* the inputs made by the PF were mainly nose-up,
* the descent lasted 3 min 30, during which the airplane remained stalled. The angle of attack increased and remained above 35 degrees,
* the engines were operating and always responded to crew commands.
- The last recorded values were a pitch attitude of 16.2 degrees nose-up, a roll angle of 5.3 degrees left and a vertical speed of -10,912 ft/min.
The flight trajectory of the last 6 minutes (Graphics: BEA):
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By Simon Hradecky, created Friday, Feb 4th 2011 14:09Z, last updated Friday, May 27th 2011 13:18ZToday (Feb 4th 2011) the French BEA have disclosed details of the 4th search phase for the wreckage and black boxes of flight AF-447, which is going to start March 15th 2011 and last until July 2011 in three stages of 36 days (30 days search, 6 days transit for stop overs in Brazil) each. Three submarines (Remus 6000) are being used together with their exploration vessel "Alucia". This phase is dedicated to locate debris and the black boxes, uses small ships and is less expensive (9.3 Million Euros/12.5 Million US$) being funded by Airbus and Air France.
Should phase 4 locate the wreckage, the BEA will immediately trigger phase 5 which is to recover the located wreckage. This phase is deemed expensive and will be funded by the state.
Phase 4 is going to search an area of 10,000 square kilometers following 7,000 square kilometers being covered in the previous three search phases, so that the complete area of 40nm around the last known position of flight Air France AF-447 (17,000 square kilometers/5,000 square nm) will be covered.
On Apr 3rd 2011 investigators of the BEA said, that in the last 24 hours debris has been recovered from the Atlantic Ocean floor which has been identified to belong to the crashed Airbus A330-200 registration F-GZCP. The debris was "relatively concentrated", investigators now believe they have located the actual main wreckage site. There is still no guarantee though that the flight data recorders will be found. More information will be released in a press conference in Paris on Apr 4th 15:00L (13:00Z).
In the press conference of Apr 4th the BEA released a number of graphics and photos (see below) showing the location of the main wreckage site as well as some underwater pictures of the debris found.
On Apr 8th the BEA announced, that the fifth phase of the search and recovery operation funded by the French government (as lined out above) has been invoked and will be carried out by the ship "Ile de Sein" of Alcatel-Lucent Submarine Networks (ASN) carrying a remotely operated vehicle from Phoenix International Inc.
On Apr 27th 2011 the BEA announced, that the recovery work has started. During the first more than 12 hours' dive of Remora 6000 the chassis of the flight data recorder, however without the crash surviveable memory unit containing the data, was found surrounded by debris from other parts of the aircraft.
On May 1st 2011 the BEA reported they have located and recovered the crash surviveable memory unit of the flight data recorder (see pictures below).
On May 3rd 2011 the BEA located and recovered the complete cockpit voice recorder from the ocean floor. Both black boxes will now be taken to Cayenne (French Guyana) by a French Navy's patrol boat, from where the recorders will be flown to Paris, where the recorders are expected to arrive in 10 days.
On May 9th 2011 the BEA reported the Navy patrol boat has reached the recovery ship, received the black boxes under judicial seal and is on the way to Cayenne. The black boxes are then expected to arrive in Paris by Thursday (May 12th). In the meantime an engine and the avionics bay of the A330 have been recovered both of which contain onboard computers (editorial note: with long term storage devices recording the operating status like the electronic engine control EEC or quick access recorders).
On May 12th 2011 the black boxes arrived in Paris. The BEA released an overview of the wreckage and identified parts on the ocean floor (see below).
On May 16th 2011 the BEA announced, that they were able to download all data following an operation to open and clean the recorders and to dry the memory cards. All data of the flight data recorders as well as the last two hours of recording from the cockpit voice recorder have been downloaded. The data are now being analysed, another preliminary report is to be expected in a number of weeks (during the summer period).
Wreckage location Overview (Graphics: BEA):
The black boxes being transferred to the patrol board (Photo: BEA):
An engine resurfacing (Photo: BEA):
The avionic bay in the light of the day (Photo: BEA):
The cockpit voice recorder including crash surviveable memory unit recovered May 3rd 2011 (Photo: BEA):
The crash surviveable memory unit recovered May 1st 2011 (Photo: BEA):
The crash surviveable memory unit recovered May 1st 2011 (Photo: BEA):
Chassis of flight data recorder found on ocean floor (Photo: BEA):
Map of wreckage area (Graphics: BEA):
Sonar Image of wreckage area (Graphics: BEA):
An engine (Photo: BEA):
Part of the fuselage (Photo: BEA):
Landing gear (Photo: BEA):
The Remus 6000 submarine with an exploration vessel (Photo: WHOI):
Search map showing previous searches and the area of the new search around Last Known Position LKP (Graphics: WHOI):
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By Simon Hradecky, created Thursday, Nov 25th 2010 22:29Z, last updated Thursday, Nov 25th 2010 22:29ZFrance's Secretary of State for Transport Thierry Mariani announced on Nov 25th 2010, that a fourth search for the flight data recorders is planned to commence by February 2011 involving the best equipment available.
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By Simon Hradecky, created Friday, May 7th 2010 08:05Z, last updated Friday, Jun 11th 2010 10:28ZThe BEA denied widespread media reports surfacing during May 6th, that the black boxes were found or located. The BEA said instead late May 6th, that data analysis of recordings taken during the first phase of search within 4 weeks after the crash has identified a zone of possibility spreading over an area of a few tens of square kilometers. That zone is located about 2 ship hours south of the locations searched so far. The search is now expanding into that zone of possibility as well.
The false media reports were based on a statement by a French deputy minister early May 6th 2010, that the black boxes have been found. The deputy minister adjusted his statement during the day that the black boxes had been located to an accuracy of 5km.
The Aviation Herald never believed that report arguing, that it was highly unlikely the black boxes were located at a time when the ships were in Recife (Brazil) for recrewing, resupplying and reorganisation of the search (BEA statement released May 4th 2010), and also arguing, that if the black boxes no longer sending any signals were found, underwater robot equipment must actually have established visual contact, so that not knowing the coordinates with a precision of a few meters would be incomprehensible.
On May 12th the BEA reported, that the search in the zone of possibility did not turn up anything. The searchers have returned to the original search area.
On Jun 10th the BEA said, that the third phase of search has ended on May 24th without locating the wreckage or black boxes of the aircraft. 6300 square kilometers of search area had been combed in that third phase of search bringing the total of surveyed area close to 17000 square kilometers. The BEA is currently evaluating the results of the three phases of search.
Total area surveyed in the three phases of search (Graphics: BEA):
Third phase planned search [yellow] (Graphics: BEA):
![Third phase planned search [yellow] (Graphics: BEA)](http://avherald.com/img/af_a332_f-gzcp_atlantic_090601_22.jpg)
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By Simon Hradecky, created Thursday, Dec 17th 2009 16:27Z, last updated Thursday, Dec 17th 2009 16:27Z | | Location of recovered debris (Graphics: BEA) |
The French BEA have released their second English interim report adding new information regarding the wreckage parts recovered, weather situation, the decoding of ACARS messages, certification and continuing airworthiness of the pitot probes as well as about other events with unreliable airspeed.
All materials recovered so far were made of low density honeycomb or composite materials and include the radome, parts of the cabin, cargo compartment, wing, belly fairing and lower deck mobile crew rest. Most of the debris could be located according to its position in the aircraft using serial numbers or comparism according to shape, coating color, materials and documentation of the manufacturer where serial numbers were not available.
The life jackets recovered were all in their packages.
29 passenger oxygen containers were found in the debris. Deformations on three damaged showed, that they were in their non-deployed position. Other less damaged containers although open had their pins still in place, which close the oxygen circuit, showing the oxygen flow had not been activated.
Recovered control surfaces include some aileron parts and some elevator parts, all of which show damages caused by a bottom-upward load.
Parts of the flap track fairings enabled analysis showing, that the flaps were in their retracted position.
Analysis of the rudder damage show, that the rudder's hinge axis experienced a relative load of more than 36G relative to the vertical stabilizer.
The seat belts of the cabin crew seats were not used at time of impact.
All damages were symmetric, no lateral forces became evident through the damages. All debris shows evidence of a high rate of descent at the time of impact with the water. The damages are not compatible with a separation of the aft part of the fuselage in flight. The left/right symmetry indicates, that the airplane had little bank/sideslip at impact. The damages are not consistent with a nose low attitude at time of impact.
The BEA concludes from the damages, that the airplane was probably intact at the time of impact with the water, the airplane struck the water with a nose up attitude, low bank and a high rate of descent.
Autopsies were performed on 50 bodies, 45 passengers, 4 flight attendants and the captain. All injuries, mainly fractures of the spinal column, are compatible with a high upwards acceleration on a seated person. The autopsy of the captain does not allow a conclusion to the location of the captain at the time of impact.
Explanation of ACARS messages:
NAV TCAS FAULT:
The NAV TCAS Fault message is only compatible with one mode, in which an internal TCAS monitoring process which applies to the altitude parameter. The active transponder's altitude information (received from air data reference ADR 1 or ADR 2) is subjected to a credibility test, in which TCAS computes an altitude prediction and compares it with the actual altitude. If the two parameters move too far apart, TCAS stops operating and generates this specific ECAM message. Once the altitude becomes credible again, TCAS would resume operation.
PFD FPV flags:
The flight path vectors FPV would be completely removed from the captain's and first officer's primary flight displays only if one of the three conditions are met for each of the three air data references:
- barometric vertical speed higher than 20,000 feet per minute
- true airspeed higher than 599 knots
- measured calibrated airspeed is less than 60 knots
Once the parameters come within normal operating ranges again, the FPV indications would resume.
F/CTL PRIM 1 FAULT:
The message indicates, that the flight control master computer 1 has stopped working either as result of a command or as a result of a failure. In the absense of an associated fault message, it is not possible to command a shut down. A fault message can not be excluded, it might have been still queued for transmission, but could not be sent anymore.
F/CTL SEC 1 FAULT:
Same as F/CTL PRIM 1 FAULT, however associated to flight controls secondary control computer.
Maintenance Status ADR2:
Three possible fault messages concern a monitoring process checking the coherance of static pressure, total pressure and angle of attack delivered by the three ADRs. in the case of ADR2 one of these monitoring processes has detected a deviation greater than a preset threshold between its own parameters and those of ADR1 and ADR3.
ISIS (22FN-10FC) SPEED OR MACH FUNCTION:
The only possibilities of excursion of the envelope consistent with the other messages has been identified to be:
- a calibrated airspeed higher than 530 knots without Mach exceeding 1.0. This condition implies, that the aircraft was between 4000 and 14000 feet.
- the difference between total and static pressure being lower than a given threshold. Notably this includes the case that the static pressure is higher than the total pressure.
The "HARD" nature of the message indicates, that the condition existed for longer than 2 seconds.
ADIRU2 (1FP2):
This message was created by IR2 (Inertial Reference Unit 2) indicating, that it considered all three ADRs invalid with at least one parameter (barometric altitude, barometric vertical speed and true airspeed) being inconsistent. It is logical, that as soon as one IR produced that fault message upon rejecting the third ADR, the other two IRs would produce such a message, too.
The fact, that EFCS1 was amongst the identifiers, permits to state that at least two primary flight control computers rejected the ADRs. It has not been possible yet to understand, why EFCS2 - the clone of EFCS1 - was not amongst the identifiers.
The analysis of the fault messages:
At least one message must have been pending for transmission at the time of impact. That message should have been transmitted at 02:15:14 UTC at the very latest, but was not transmitted.
According to the attitude information derived from the debris the airplane was in a nose up almost wing level attitude and therefore should have been able to transmit ACARS messages to the very last second of flight. This would suggest an end of flight between 02:14:26Z and 02:15:14Z.
The preliminary analysis highlights an inconsistency in the speeds measured just after 02:10Z, which generated 10 of the 24 messages in that minute. 11 other messages between 02:11 and 02:14 can also be linked anemometric problems like speed inconsistencies, low speed or erratic speed values.
The airplane switched to Alternate Law at 02:10Z and remained in that law until end of flight.
No message indicates the loss of displays or inertial information (attitudes).
The BEA annotates, that the messages show significant differences to flight QF-72 in both content and sequence. QF72 experienced problems with the ADIRU, see Accident: Qantas A333 near Learmonth on Oct 7th 2008, sudden inflight upset injures 74 people on board.
The BEA studied 13 cases of losses or temporary anomalies of speeds. Several notable points were derived:
- all flight levels were between 340 and 390
- the air masses were highly unstable and were the seat of deep convection phenomena
- the crews reported no significant radar echos on the chosen flight path, however observed active zones nearby or lower. A study by Meteo France is being conducted on this on request by BEA.
- three crews reported observing ice or rain.
- all events occured in instrument meteorological conditions.
- the recordings of total or static temperature show increases of 10 to 20 degrees C which sometimes began before the crew noticed speed anomalies (in one event the increase was lower).
- turbulence was always recorded and observed, levels reported by crews varying from light to severe. The recorded minimum/maximum accelerations ranged from 0.75-1.2G to 0.2-1.9G.
In all cases:
- the autopilot disengaged without crew intervention
- the crews were able to use autoflight systems (autopilot, autothrust) again
- in 12 cases the airplane switched to alternate law until end of flight
- the autopilot disconnection was associated with the removal of flight director indications and sometimes other parameters, in all cases the flight director reappeared during the event, in some cases when two speed values were recorded coming close again
- in seven cases the autopilot reconnected during the event, in two cases when the speed values were close to each other but erroneous
- the autothrust disconnected in 10 cases resulting in thrust lock activation. In five cases the ThrustLock function remained active for over one minute.
- in two cases the autothrust did not reconnect and the flight director did not reappear. The recording of engine RPM N1 parameters showed fluctuations between 48 and100%.
- the speed anomalies can be categorized as intermittent falls (peaks) and falls followed by levelling off, that were accompanied by an instant increase in dispayed static temperature and a "drop" in altitudes. In two cases the lower speed limits recorded were below 100 KIAS.
- the maximum continuous duration of anomalies was 3 minutes 20 seconds.
- when the speeds of the ISIS systems were recorded, their anomalies possessed signatures that were different from the indications on the captain's instruments.
Crew reactions to the reappearance of the flight directors on the PFD include the rapid reengagement of the autopilot and autothrust systems. While the speeds may be close to each other, they may be erroneous however leading the autoflight systems to command movements of the flight control surfaces that may be inappropriate for the real speed of the airplane. (Editorial note: bold set by the editor, who thinks this may be a very significant sentence in the report, page 53 top paragraph).
In case of an automatic disconnection of the autothrust system with activation of the ThrustLock Function, the absense of manual adjustment by crew can present a risk of an attitude/thrust mismatch especially if the disconnect occured at a low N1 value. (Editorial Note: bold added by the editor, this sentence may be significant, page 53 second paragraph).
By November 3rd Airbus has identified 32 cases of erroneous air speed indications between Nov 12th 2003 and Jun 1st 2009. 2 of the events were the result of pitot probe obstruction/possible destruction by ice. 11 events happened in 2008 and 10 in the first 5 months of 2009. In 26 cases the aircraft was equipped with AA Thales probes, in two cases with BA Thales probes and in one case with a Goodrich probe.
All Air France Airbusses A330s were initially equipped with Goodrich 0851GR probes. Following a number of speed fluctuation events or speed indication losses the French DGAC published an airworthiness directive in 2001 which demanded the replacement of the Goodrich 0851GR probe with either the Thales probes or the Goodrich 0851HL probe before the end of 2003. In accordance with that AD Air France equipped their A340 and A330 fleet with the AA Thales probes.
Following speed inconsistencies in heavy precipitation or icing conditions on A320s and other types Airbus published a non-mandatory Service Bulletin recommending the replacement of the Thales AA probes with the BA type. In absence of observed speed inconsistencies Air France chose to apply the Service Bulletin only in case of pitot failure.
In September 2008 Air France had observed a number of speed inconsistencies and approached Airbus asking, whether the BA type would resolve this inconsistencies, but received the reply, that the BA type would improve performance in heavy precipitation but not with ice crystals. In October 2008 Air France alerted Thales of the increasing problem of probe icing prompting Thales to open an internal technical analysis.
On Nov 12th Airbus modified their Service Bulletin removing the mention of ice crystals.
New meteorological analysis shows the presence of strong condensation towards AF-447's flight level probably associated with convection phenomena. The precise composition of cloud masses above FL300 is little known, especially with regards to super-cooled water/ice crystal diving, especially with regards to the size of the latter.
Several airplanes flying before or after AF-447 at about the same altitude altered their course to avoid the cloud masses. (Editorial note: bold added, may prove significant)
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By Simon Hradecky, created Sunday, Nov 8th 2009 17:13Z, last updated Sunday, Nov 8th 2009 17:15ZIn a memorial held in Rio de Janeiro France's Minister of State for Cooperation said, that the third phase of search for the black boxes will commence in February 2010.
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By Simon Hradecky, created Friday, Aug 21st 2009 10:02Z, last updated Friday, Aug 21st 2009 10:02ZThe French BEA said in a press release, that the second phase of search for the black boxes has ended, the oceanographic vessel "Pourquoi pas?" is expected back in Dakar (Senegal).
The search surveyed an area of 75km in diameter around the last known position of the aircraft (N02.98 W30.59) thus covering an area of about 18000 square kilometers (5250 square nautical miles). The search did not find the remains of the aircraft or the black boxes.
A third phase of the search will commence in the coming weeks following a meeting between BEA, investigators and specialists analysing available data thus far.
Airbus had pledged to invest up to 20 million Euros into the search for the black boxes if the need arises enabling this third phase of search to last for three months.
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By Simon Hradecky, created Friday, Jul 31st 2009 13:50Z, last updated Friday, Jul 31st 2009 16:56ZAirbus Industries have decided to invest up to 20 million Euros (US$ 27.8 million) into the search for the black boxes of the crashed Air France Airbus, the company announced on Friday (Jul 31st). This will ensure at minimum an additional three months of search for the missing recorders. Airbus said, that they want to definitely know what happened.
Airbus Industries had released a recommendation to all operators of Airbus aircraft yesterday (Jul 30th), that all A320, A330 and A340 aircraft should be equipped with at least two Goodrich rather than Thales pitot probes following a new incident, during which an Airbus A320-200 equipped with the improved Thales probes lost airspeed information for about one minute, see: Incident: Air France A320 enroute on Jul 13th 2009, unreliable airspeed for one minute.
Air France have announced, that they are going to follow the recommendation by Airbus and replace the Thales with the Goodrich pitot sensors on their aircraft.
The European Aviation Safety Agency (EASA) announced on Friday (Jul 31st) to make the recommendation by Airbus Industries mandatory shortly.
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By Simon Hradecky, created Saturday, Jul 18th 2009 15:04Z, last updated Saturday, Jul 18th 2009 15:04ZA 10 meter (30 feet) long piece of debris thought to belong to the fuselage of the Air France Airbus A330-200 has been found at the beaches of Gyuana (main city Georgetown) about 1650nm westnorthwest of the last known position of the aircraft by a fisherman on Wednesday (Jul 15th), a spokeswoman for Guyana's Civil Aviation Authority reported.
However, the part may also belong to an Ariane space rocket, that was launched in French Guyana on July 1st.
Map (Courtesy Google Earth):
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By Simon Hradecky, created Wednesday, Jul 15th 2009 15:14Z, last updated Wednesday, Jul 15th 2009 15:16ZThe French BEA announced, that the search for the wreckage and flight data recorders on the ocean floor will continue with the help of the oceanographic vessel "Pourquoi pas?", that is going to join the search next week. This phase of the search is scheduled to last for another month and involves diving vehicles and a towed sonar.
The debris parts collected from the ocean so far have reached France and are now being examined by the BEA.
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By Simon Hradecky, created Saturday, Jul 4th 2009 08:33Z, last updated Wednesday, Jul 8th 2009 11:01ZIn response to the report put forward by the French BEA and aiming to remove doubts about procedures adopted by Brazil's Civil Aviation Authority Brazil's Air Media Center clarified, that a flight plan was provided by the airline to all relevant air traffic control centers along the flight path of the airplane (the BEA had reported Dakar was not in possession of a flight plan).
At 01:33Z flight AF-447 did forward an estimate of 02:20Z for waypoint TASIL (the BEA states in their report, that that estimate was not provided despite three repeated requests by Brazil's Atlantic control). The position estimates were immediately phoned to Dakar ATC, the receipt of the estimates were acknowledged by Dakar (the BEA states, that Dakar requested such data at 01:48Z as they did not have a flightplan).
The FAB also states, that Recife Control issued alert at 05:40Z (the BEA reported, alert was issued by Brest Control Center at 08:15Z) and started the search for the airplane following the inquiry of Dakar about AF-447s position at 04:40Z, with sun rise the first search airplane was already in the air overflying the route that AF-447 had been following for a visual search.
At no time any ELT signals or distress calls (including on the international emergency frequency) were recorded.
According to operational agreements between Brazil and Senegal there is no need to have a formal communication between the air traffic control centers to transfer the airplane from one control zone to the other, if the airplane is to overfly the control zone boundaries within 3 minutes of its coordinated estimate. There was no formal transfer of AF-447 therefore, starting 02:20Z the airplane was (theoretically) under the control of Dakar.
On Jul 8th The Aviation Herald received additional information to a possibly related incident. The information states, that data collected by Delta Airlines since 2006 support the theory of blockages of the pitot tubes rather than icing. About 1 in 83,300 flights have been affected by unreliable airspeed encounters since 2006, all events occuring between FL330 and FL400 in moderate or stronger turbulence. All events took place between May and December (none between December and May) and all events took place on latitudes between 3 degrees North and 37 degrees North. See: Incident: Northwest A333 over East China Sea on Jun 23rd 2009, unreliable airspeed.
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By Simon Hradecky, created Thursday, Jul 2nd 2009 16:37Z, last updated Thursday, Jul 2nd 2009 16:37ZThe BEA have released their preliminary reports in both English (3MB - without attachments) and French (13MB) reporting, that the airplane had taken off from Rio de Janeiro at 232.8 tons near its maximum takeoff weight (233 tons) at 22:29Z. The airplane was subsequently cleared to FL350. At 01:35Z the crew contacted Brazil's Atlantic air traffic control control on the HF frequency reporting, they had just overflown waypoint INTOL, giving estimates for waypoints SALPU at 01:48Z and ORARO at 02:00Z. The crew also transmitted their SELCAL code and a test was performed.
The controller subsequently asked them to maintain FL350 and provide an estimate for TASIL, repeating the request for three times without reply.
The airplane's ACARS was programmed to transmit its own position about every 10 minutes. The last position transmitted at 02:10Z was 02 degrees 58.8 minutes North and 30 degrees 35.4 minutes West (N02.98 W30.59).
Analysis of the weather infrared images produced by the Meteosat 9 satellite every 15 minutes, with an image taken about 7 minutes before and another 7 minutes taken after the last position report at 02:10Z, does not allow conclusions, that the weather was exceptional, but shows the existance of a cluster of powerful cumulonimbi along the planned flight path starting at 00:30Z. The cluster is the result of 4 smaller clusters combining, its east-west extension was some 400km (216nm). By around 02:00Z those cumulonimbi had reached their maturity, it is therefore highly probable that some produced notable turbulence at FL350. It is also possible, that there was significant electrical activity at that flight level. The existance of supercooled water however is not very probable.
Dakar Air Traffic Control requested information about flight AF-447 from Brazil's Atlantic Control by phone on 01:48Z as he had no flight plan, and later coordinated the airplane with Cape Verde Control. He told Cape Verde at 02:48Z, that he had not made contact with AF-447. At 04:21Z Dakar asked Brazil's Atlantic control by phone to confirm, that the airplane had passed TASIL. Brazil confirmed that the airplane was estimated TASIL at 02:20Z at FL350, but no contact was made. Dakar computed an estimate of 03:45Z for entering the airspace of Cape Verde, but Cape Verde reported at 04:39, that no contact had been made. At 05:09Z Brazil's Atlantic Control had rechecked the estimates and called Dakar about news from flight AF-447 asking, whether the airplane was already under Cape Verde Control, to which Dakar replied "Yes, no worry."
At 04:11Z Dakar Control had asked flight AF-459 to contact AF-447. By 04:18Z AF-459 asked Air France Dispatch to contact AF-447. At 4:24Z Air France sent an ACARS message to AF-447.
At 05:50Z after several unsuccessful attempts to establish contact with AF-447 Air France contacted the Search and Rescue Satellite Aided Tracking center, but no emergency beacon had been registered.
At 06:13Z Brest Center contacted by Air France and coordinating first attempts to locate the airplane said, that according to an indirect source that had not been validated flight AF-447 had been in contact with Moroccan ATC.
At 06:35Z Madrid Center told Brest, that flight AF-447 was in touch with Casablanca and would enter Lisbon control zone within 15 minutes.
At 06:44Z Air France Dispatch established, that Casablanca was not in touch with AF-447, but AF-459.
After verifying with a number of control centers Brest raised alert at 08:15Z.
Following 25 ACARS Messages were received from the airplane:
| 2:10:10 - | .1/WRN/WN0906010210 221002006 | AUTO FLT AP OFF | | 2:10:16 - | .1/WRN/WN0906010210 226201006 | AUTO FLT REAC W/S DET FAULT | | 2:10:23 - | .1/WRN/WN0906010210 279100506 | F/CTL ALTN LAW | | 2:10:29 - | .1/WRN/WN0906010210 228300206 | FLAG ON CAPT PFD SPD LIMIT | | 2:10:34 | #0210/+2.98-30.59 | | | 2:10:41 - | .1/WRN/WN0906010210 228301206 | FLAG ON F/O PFD SPD LIMIT | | 2:10:47 - | .1/WRN/WN0906010210 223002506 | AUTO FLT A/THR OFF | | 2:10:54 - | .1/WRN/WN0906010210 344300506 | NAV TCAS FAULT | | 2:11:00 - | .1/WRN/WN0906010210 228300106 | FLAG ON CAPT PFD FD | | 2:11:15 - | .1/WRN/WN0906010210 228301106 | FLAG ON F/O PFD FD | | 2:11:21 - | .1/WRN/WN0906010210 272302006 | F/CTL RUD TRV LIM FAULT | | 2:11:27 - | .1/WRN/WN0906010210 279045506 | MAINTENANCE STATUS EFCS 2 | | 2:11:42 - | .1/WRN/WN0906010210 279045006 | MAINTENANCE STATUS EFCS 1 | | 2:11:49 - | .1/FLR/FR0906010210 34111506 | EFCS2 1,EFCS1,AFS,,,,,PROBE-PITOT 1X2 / 2X3 / 1X3 (9DA),HARD | | 2:11:55 - | .1/FLR/FR0906010210 27933406 | EFCS1 X2,EFCS2X,,,,,,FCPC2 (2CE2) /WRG:ADIRU1 BUS ADR1-2 TO FCPC2,HARD | | 2:12:10 - | .1/WRN/WN0906010211 341200106 | FLAG ON CAPT PFD FPV | | 2:12:16 - | .1/WRN/WN0906010211 341201106 | FLAG ON F/O PFD FPV | | 2:12:51 - | .1/WRN/WN0906010212 341040006 | NAV ADR DISAGREE | | 2:13:8 - | .1/FLR/FR0906010211 34220006 | ISIS 1,,,,,,,ISIS(22FN-10FC) SPEED OR MACH FUNCTION,HARD | | 2:13:14 - | .1/FLR/FR0906010211 34123406 | IR2 1,EFCS1X,IR1,IR3,,,,ADIRU2 (1FP2),HARD | | 2:13:45 - | .1/WRN/WN0906010213 279002506 | F/CTL PRIM 1 FAULT | | 2:13:51 - | .1/WRN/WN0906010213 279004006 | F/CTL SEC 1 FAULT | | 2:14:14 - | .1/WRN/WN0906010214 341036006 | MAINTENANCE STATUS ADR 2 | | 2:14:20 - | .1/FLR/FR0906010213 22833406 | AFS 1,,,,,,,FMGEC1(1CA1),INTERMITTENT | | 2:14:26 - | .1/WRN/WN0906010214 213100206 | ADVISORY CABIN VERTICAL SPEED |
The position report was timestamped at 02:10:34Z between two maintenance messages.
The message protocol required, that the airplane's ACARS system requested communication, got assigned a channel, transmitted the data, awaited acknowledgement (after the data were transmitted from the satellite to the ground station) and closed down the communication for each message. The messages therefore arrived with a spacing of at least 5-6 seconds.
No satellite phone communications were registered from the aircraft.
The fault message "PROBE PITOT 1+2 / 2+3 / 1+3 (9DA)" means, that a speed decrease of more than 30 knots was detected within one second. The three air data units were considered valid at that time.
The fault message "FCPC2(2CE2)/WRG:ADIRU1 BUS ADR1-2 TO FCPC2" indicates, that the information provided by ADR1 via bus 2 is no longer considered valid by the primary flight controls computer 2, the code indicating, that the other primary flight control computers had not detected that fault according to the ATA code 27 (otherwise ATA code 34 would follow). This message has not yet been explained.
The fault message "ISIS (22FN-10FC) SPEED OR MACH FUNCTION" indicates, that there had been an internal failure of the calibrated air speed or mach computation, or calibrated air speed or mach were outside certain limits.
The fault message "ADIRU2 (1FP2)" has not yet been explained.
The fault message "FMGEC1 (1CA1) (2 h 13)" has not yet been explained.
The warning messages indicate, that various monitoring processes have been triggered, at least one of them related to air speed measurement inconsistency.
The cockpit effect messages mean:
- AUTO FLT AP OFF: The autopilot disconnected without crew intervention
- AUTO FLT REAC W/S DET FAULT: windshear detection is unavailable
- F/CTL ALTN LAW: FBW switched into alternate law (protections lost)
- FLAG ON CAPT PFD SPD LIM and FLAG ON F/O PFD SPD LIM: characteristic speeds (green dot, VLS, ...) lost due to loss of calculating function
- AUTO FLT A/THR OFF: Autothrottle disconnected other than by crew intervention or throttle levers were moved into the idle notch
- NAV TCAS FAULT: TCAS is inoperative, the message has not yet been explained
- FLAG ON CAPT PFD FD and FLAG ON F/O PFD FD: flight director bars have been removed from primary flight displays
- F/CTL RUD TRV LIM FAULT: The rudder limiter value computation is unavailable, the rudder remains limited to the present values until slat extension
- MAINTENANCE STATUS EFCS2 and MAINTENANCE STATUS EFCS1: not brought to the crew attention
- FLAG ON CAPT PFD FPV and FLAG ON F/O PFD FPV: flight path vector displays removed from the primary flight displays, red flags shown instead
- NAV ADR DISAGREE: Computers have rejected one ADR and then detected a disagreement between the remaining ADRs on one of the monitored paramenters.
- F/CTL PRIM 1 FAULT: Primary Flight Controls Computer 1 has stopped functioning either as result of a command or failure
- F/CTL SEC 1 FAULT: Secondary Flight Controls Computer 1 has stopped functioning either as result of a command or failure.
- MAINTENANCE STATUS ADR2: not brought to crew attention
- ADVISORY CABIN VERTICAL SPEED: cabin pressure changes at a rate of 1800 feet/minute or greater for 5 seconds.
Visual inspection of the recovered debris showed, that the tail fin broke during a forward motion with a slight twist to the left. The galley recovered and identified as G2 was basically intact, but baskets and racks were compressed in the lower part of both galley carts. A toilet door showed evidence of great compression force. The floor of the crew rest module was bent upwards under the effect of a strong upward pressure from below, the connecting brackets between floor and wall were bent backwards.
The BEA concludes the analysis: "Observations of the tail fin and on the parts from the passenger (galley, toilet door, crew rest module) showed that the airplane had likely struck the surface of the water in a straight line, with a high rate vertical acceleration."
The bodies of about 30 victims recovered were all clothed and relatively well preserved. At this time of the investigation the BEA still did not have access to the autopsy results, the report states (English version, end of page 37).
Flight Track (Graphics: BEA):
Map of locations of recovered debris, red circles mark locations of bodies (Graphics: BEA):
Weather infrared satellite image Meteosat-9 (Image: BEA):
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By Simon Hradecky, created Thursday, Jul 2nd 2009 13:11Z, last updated Thursday, Jul 2nd 2009 15:22ZThe BEA has concluded their press conference introducing the results of their investigation and their preliminary report so far.
The key sentences have been (according to simultaneous English translation by BEA):
- No technical problems with the airplane before the takeoff.
- The airplane did NOT break up in flight.
- The 24 ACARS messages refer to the loss of airspeed (pitot tubes)
- The airplane also lost information about the direction the airplane was going to.
- The airplane hit the ocean in a flat attitude at high vertical speed.
- Weather was a classic ITZ scenario.
Nothing had been found before June 6th, then the first bodies and parts have been found. Parts from the nose to the tail of the airplane have been found including parts of the structural body of the airplane, one part of the engine and parts of the main cabin have been recovered. No clothes have been found, recovered life vests were not inflated. 51 bodies were recovered.
One of the cockpit walls has been found deformed. A large part of the crew rest room has been found, impact marks indicating that something came from the bottom up to the top. The debris recovered so far suggests, that the airplane did not break up in flight, but went down vertically.
Three other flights (IB-6024 [A343, Rio De Janeiro GIG-Madrid MAD 12 minutes behind AF-447], LH-507 [B744, Sao Paulo GRU-Frankfurt FRA] 20 minutes behind AF-447, AF-459 [A332, Sao Paulo GRU-Paris CDG 37 minutes behind AF-447]) tracked the same route to TASIL between FL350 and FL370 around the time of the crash. They all had to avoid storm cells and diverted from the airway between 11 and 80nm. They experienced moderate turbulence. All three flights had problems to establish communication with Dakar. There were no satellite phone conversations from those crews.
The weather in the Intertropical Convergence Zone was a classic scenario with storm cells.
The airplane had started the engines at 22:10Z and got airborne at 22:29Z. Last radio communication was at 01:35Z. No transfer had been completed from Rio's control to Dakar control. An attempt by the AF-447 crew to establish contact with Dakar Control has been detected at 02:01Z (the wording to the means of communication was unclear, supposedly it was a digital data transmission via ACARS). No distress call was detected.
First alerts were sent at around 8:30 (unclear whether GMT, local Europe, local Brazil).
The BEA refuses to believe, the black boxes would not be found, however stated, that the search for the recorders will be terminated on July 10th.
The Original BEA English translation said: The airplane went down vertically, a review of French wording offers a different picture however stating, that the airplane came down in a flat attitude at high vertical speed.
The full preliminary report has just been published: French Version (13MB) and English Version (3MB).
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By Simon Hradecky, created Saturday, Jun 6th 2009 17:46Z, last updated Thursday, Jul 2nd 2009 19:12Z | Debris sighted on June 6th
(Photo: FAB) |
Forca Aerea Brasileira (FAB) have announced today (Jun 6th), that they have found two male bodies today as well as a blue chair (serial number 23701103B331-0 not yet confirmed to be part of F-GZCP), a bag with a vaccination card and a leather briefcase, which contained a ticket for flight AF-447 and a laptop. The bodies and debris were found about 1200km off the coast of mainland Brazil and about 69.5km northwest of the airplane's last ACARS position report.
Air France confirmed the ticket number to be a valid ticket for flight AF-447.
Later the day around 16:00 local the Hercules C-130 spotted another debris field (most interesting find see photo) west of the location, where the two bodies had been found.
Two ships are collecting the debris located so far. The search operation however has still priority to find the other 226 people over locating/recovering debris. Each new find so far has reinforced the need to expand the search area, that already spans more than 200,000 square kilometers (almost the size of the United Kingdom).
Air France said, that Airbus Industries had issued a recommendation to retrofit the pitot tubes in September 2007, giving the operators full freedom to decide about the implementation of the recommendation. Air France had implemented the recommendation to their A320 fleet, but did not retrofit the long range A330s and A340s due to the absence of incidents. Starting May 2008 Air France however observed the loss of air data on their A330 and A340 fleet. These incidents were discussed with Airbus Industries, who identified the problems as icing related and suggested that the modification implemented on the A320 would not resolve the icing issue. In the first quarter of 2009 laboratory tests however proved, that the new pitot tube design establishes a significant improvement over the previous design. Following a test flight Air France began to implement the retrofit of the new design pitot tubes onto their A330 and A340 fleet on April 27th 2009. Without prejudice Air France has now decided to accelerate that program to retrofit the pitot tubes on the A330/A340 fleet.
On June 11th Air France added, that the necessary spare parts arrived on May 29th (two days prior to the crash) and the replacement program commenced that day. Airbus Industries and EASA maintain, that the operation of aircraft is safe with all types of pitot tubes.
Air France reported on Jun 25th, that two crew members have been identified amongst the human remains recovered from the Atlantic: the captain of the flight and a flight attendant.
The FAB reported on Jun 26th, that they have ended the search operation for human remains and debris. A total of more than 600 pieces of debris as well as 51 mortal remains have been recovered, the FAB preferring to use the term "remains" over "bodies" due to the condition of the bodies. The last remains were discovered on Jun 17th with no new sightings since. More than 2 million square kilometers have been searched, 1612 people, 12 aircraft and 11 ships were involved in the search. The crews, navy command and FAB offer their reverence to all victims and their families.
The FAB reported on Jun 23rd, that Senegalese Authorities have ended their participation in the search operation and have withdrawn their vessels and search airplanes. The FAB is continuing the search including areas in Senegalese airspace (following earlier agreements with Senegal permitting operation of Brasilian airplanes and vessels in the search area).
The Task Force consisting of Federal Police and the Department of Social Defense reported on Jun 21st, that 11 of the 49 victims brought to Recife so far (one still on the way to Recife), have been identified. 10 of the 11 are Brasilians. Search efforts are in the process of being reduced, one of the search airplanes employed since June 1st has been withdrawn from the operation.
The French BEA in charge of the investigation into the crash reported, that they did not yet receive results of the autopsies from the Brasilian Authorities nor were their medical staff permitted to participate in the autopsies. Brasilian Authorities are in charge of the search and recovery operation. The Brasilian Task Force responded, that participants from France must be properly accredited through diplomatic channels, four French personnel have already been accredited on Jun 10th as observers into the work.
There is no official or independent verification for the Jun 23rd report of a single French newspaper fueling a media hysteria at the moment, that weak signals of the black boxes may have been heard. Neither the French Marine, BEA nor Brasilian Authorities confirm (Jun 23rd 09:00Z), that any signals have been heard. The BEA actually denied, that any signals of the black boxes have yet been heard so far. Many signals had been heard during the search so far and were investigated, but did not originate from the black boxes. A spokesman for the French government said (Jun 23rd 9:20Z), that no signals have been received.
The Federal Police as well as the Department of Social Defense in Pernambuco said on Jun 14th, that the condition of the bodies does not allow any visual identification by relatives. The necessary correction from 44 to 43 bodies recovered is due to the fact, that one of remains had to be identified as coming from a large marine animal rather than a human. Scientific examinations of the remains are underway to determine the identity of the remains and the possible causes of the accident. The proceedings follow international standards - as of current there is no prediction when the examination of the mortal remains will be concluded.
The FAB said on Jun 13th, that a merchant ship "Gammagas" on the route from Uruguay to the United Kingdom discovered and recovered the rugged structure of the aircraft about 415km northwest of St. Peter and Paul.
The FAB reported on Jun 10th, that the worsening weather did not impact the recovery operations although search planes were directed at other routes with more favourable weather conditions. The French submarine "Emeraude" and the French helicopter carrier and command ship "Mistral" have arrived at the search area. After taking specialist sonar and sensor equipment from the US on board both ships will start the search for the black boxes.
Airbus Industries said in an internal e-mail leaked to the public, that there is no evidence of any electrical failure as had been initially claimed by Air France, no evidence of loss of flight instrument displays and no evidence of an ADIRU malfunction as had happened in the Qantas incidents (Qantas uses a different ADIRU manufacturer than Air France). The ACARS messages as available all indicate unreliable airspeed, although some messages suggest further aircraft evolution and/or crew actions. The last message (cabin vertical speed) indicates a loss of cabin pressure at a rate greater than 1800 feet per minute, which remains to be explained. 3 types of pitot tubes are available, 2 from Thales (BA and AA/Standard) as well as one from Goodrich. The standard Thales pitot tube AA was used on Air France's A330 F-GZCP. The BA type was developed to enhance water drainage encountered during heavy rain conditions during takeoff or landing.
According to the French pilots' union Air France have agreed to dispatch A330 and A340 aircraft only with at least two of the three pitot tubes retrofitted with the new type starting coming Tuesday (Jun 9th).
A number of images have appeared on the Internet claiming, that a memory stick has been found containing photos of onboard scenes. All of those images are fake and had been used in a TV series. Images claiming to be of AF-447 being spammed via e-mail are not just fake, but do contain malicious code executing without user intervention according to Internet Security firms.
The limitations of onboard weather radar systems in detecting weather systems and areas of turbulence are shown by an English accident report by the Hong Kong Transportation Safety Board (HTSB) into in inflight upset of a Dragon Airlines Airbus A330-300, registration B-HYA performing flight KA-60 from Kota Kinabalu (Malaysia) to Hong Kong (China) with 236 passengers and 14 crew, which encountered severe turbulence while cruising at FL410 and deviating from the airway due to weather returns on the airborne weather radar. All 12 cabin crew and 3 passengers received injuries in the upset. The HTSB concluded, that the airplane flew inadvertently into a zone of turbulent weather caused by strong convective activity associated with a tropical depression. Based on the way of how the weather radar was operated, it was highly probable, that the crew was not presented with an optimal image to enable full appreciation of the intensity and extent weather. As a result, the deviation was not initiated early enough nor large enough to avoid the weather. The decisive parapgraph 2.2.2 reads:
Weather radar detects droplets of precipitation. The strength of the return depends on the size, composition and amount of droplets. Water particles are almost five times more radar reflective than ice particles of the same size. Weather radar is therefore effective in detecting rainfall and wet hail but not effective in detecting the upper level of a storm cell where most moisture exists in a dry, frozen state, i.e. in the forms of snow, ice crystals and hail. To determine the positions of storm cells, the antenna tilt angle should be adjusted to scan the icing level, where reflective water-covered ice/hail would be abundant. Above the icing level, ice crystals have minimal radar reflectivity. Although convective activities and turbulence exist at these levels, they do not show up readily on radar. To keep track of weather in the vicinity of the flight path, the antenna tilt angle should be frequently adjusted to scan the most reflective area in the icing level band. As altitude changes or as the aircraft gets closer to the storm cell, the tilt angle has to be changed so that the radar beam keeps scanning the most radar reflective area.
To allow comparism of the images of the tails The Aviation Herald posts two pictures of the tail fin of the American Airlines Airbus A300-600 registration N14053, that crashed at Belle Harbour near New York's John F. Kennedy Airport on Nov 12th 2001 shortly after takeoff, when the airplane went through wake turbulence. The NTSB concluded in their final report, that unnecessary and excessive rudder pedal inputs caused the rudder and tail fin to separate from the aircraft causing the crash. In the report the NTSB stated, that "the entire rudder separated from the vertical stabilizer except for portions of the rudder spar structure that remained attached to hinge arm assembly numbers 2,3,4,5 and 7" (first sentence on page 52/last paragraph of chapter 1.2.12). However, the pictures of the vertical tail of Air France show the rudder still attached to the vertical stabilizer (fin). This is a very decisive difference disallowing any comparism of the accidents without further research and additional facts.
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A ship brings collected debris ashore (Photo: FAB):
Debris, Jun 17th (Photo: FAB):
Debris, Jun 17th (Photo: FAB):
Search area of June 16th (Graphics: FAB):
Positions of bodies recovered (Graphics: FAB):
Rugged structure recovered by Gammagas (Photo: FAB):
Rugged structure recovered by Gammagas (Photo: FAB):
Map with search area of 17.500 square kilometers (Graphics: FAB):
Two flight attendant seats (Photo: FAB):
More detail pictures of Jun 12th (Photos: FAB):
Media taking pictures in an arranged photo session in Recife on Jun 12th (Photo: AP/Roberto Candia):
Debris recovered from the ocean (Photos: FAB):
Tail Fin with rudder still attached of Air France Airbus A330-200 registration F-GZCP (Photos: FAB):
Tail Fin with rudder still attached of Air France Airbus A330-200 registration F-GZCP (Photos: FAB):
Tail fin of American Airlines Airbus A300-600 registration N14053 (Photo: AP/Daniel P. Derella):
Tail fin of American Airlines Airbus A300-600 registration N14053 (Photo: NTSB):
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By Simon Hradecky, created Monday, Jun 1st 2009 10:17Z, last updated Friday, May 27th 2011 13:17ZAn Air France Airbus A330-200 (CF6-80E engines), registration F-GZCP performing flight AF-447 (dep May 31st) from Rio de Janeiro,RJ (Brazil) to Paris Charles de Gaulle (France) with 216 passengers and 12 crew, is overdue at Paris Charles de Gaulle for more than three hours following a scheduled 11:15 hours flight time and estimated arrival at 11:10 CEST (09:10Z). The airplane had departed Brazil's civil radar coverage normally.
A crisis and intervention center has been setup at Paris Charles de Gaulle Airport.
Brazil has launched a search and rescue operation off their coast along the last known radar positions near the Island of Fernando de Noronha after which the airplane had failed to establish required radio communication.
There have been no reports of an unscheduled landing anywhere on Atlantic Islands or airports surrounding the Atlantic. French Authorities report, that the airplane would have run out of fuel by now.
According to Forca Aerea Brasileira (FAB) the last radio contact with the crew was about 3 hours into the flight at around 01:33Z. The crew reported flying through severe turbulence. The airplane left civil radar coverage at 01:48Z at FL350 and was expected to report next at 02:20Z. At 02:20Z the crew did not report their position as expected prompting Oceanic Control to raise alert, also informing Dakar Air Traffic Control Center.
Air France reported, that they had received an automatic message from the airplane reporting an electrical short circuit and the failure of multiple systems at 02:14Z. Air Traffic Control as well as Military Stations along the Atlantic coast of South America, Africa, Portugal, Spain and France have been alerted and attempted to contact the airplane without success. Attempts to locate the airplane using civil and military radars from both west and east coasts (including France) of the Atlantic also proved unsuccessful. The airplane entered service in 2005 and had accumulated 18870 flights hours. The captain had 11700 flight hours, one of the first officers had 3000, the other 6600 flight hours.
Sources within Air France reported, that the automatic message did not only report an electrical short circuit, but also the loss of cabin pressure. This information has been confirmed by FAB, who also stated, that the position of the airplane was given as N3.5777 W30.3744 in that message.
New information provided by sources within Air France suggests, that the ACARS messages of system failures started to arrive at 02:10Z indicating, that the autopilot had disengaged and the fly by wire system had changed to alternate law. Between 02:11Z and 02:13Z a flurry of messages regarding ADIRU and ISIS faults arrived, at 02:13Z PRIM 1 and SEC 1 faults were indicated, at 02:14Z the last message received was an advisory regarding cabin vertical speed. That sequence of messages could not be independently verified.
Airbus Industries confirmed the loss of the airplane while still maintaining the status of the airplane officially as missing.
At 14:35Z Air France extended their sincere condolences to the family members of passengers and crew on board of the airplane. Psychological assistance is available at Charles de Gaulle Airport in France as well as at the airport in Rio de Janeiro.
The French BEA (Bureau for Accident Investigation) have opened an investigation into the loss of the A330 joined by Airbus Industries.
Air France has set up hotlines for family members at 0800 800 812 within France, 0800 881 20 20 within Brazil and +33 1 57 02 10 55 from other countries.
According to the FAB the airplane was tracking from waypoint INTOL to waypoint TASIL (entry point into Senegal airspace), positions reports would have put the airplane approximately 450nm northnortheast of the Island of Fernando de Noronha and right in the largest red zone on the infrared weather satellite image by NASA at 02:14Z. Weather Services said, that clouds and severe turbulence reached up to 55000 feet in that area.
The FAB confirmed, that the pilot of a TAM Linhas Aereas flight from Europe to Brazil reported bright spots on the ocean surface in Senegal's airspace. Senegal conducted a search in that area including having the vessel "Douce France" combing the area, the search however found no trace of the missing airplane. Earlier media reports had suggested, that the "Douce France" had found debris of the airplane in the same area, in which the TAM pilot had spotted the bright spots.
The United States have pledged support in the search of the missing airplane, especially satellite imagery and analysis thereof.
This marks the first loss of an Airbus A330 in commercial operation ever. Four hull losses of Airbus A330s had occured in non-commercial flights.
The sequence of messages reportedly received via ACARS raises memories of the Accident: Qantas A333 near Learmonth on Oct 7th 2008, sudden inflight upset injures 74 people on board and Incident: Qantas A333 near Perth on Dec 27th 2008, navigation system problem, and turns attention towards the emergency airworthiness directive released by both FAA and EASA, see also EASA issues updated emergency directive regarding Airbus A330 and A340 ADIRU issues.
| Term | Explanation |
|---|
| Normal Law: | Regular operating mode of the fly by wire (FBW) including all protections. | | Alternate Law: | Some of the protections in normal law, the regular operating mode, are dropped. | | Direct Law: | The controls (sidestick) inputs are converted into direct movements of control surfaces without computations or checks. | | ADIRU: | Air Data and Inertial Reference Unit provides air data (airspeed, altimeter, ...) and positional data (attitude, position) to the instruments | | ISIS: | Integrated Standby Instrument System is a completely independent, self contained system providing a third independent set of basic instruments (attitude indicator, altimeter, airspeed indicator) to the crew | | PRIM 1: | Flight Control primary computer #1, three of them monitor each other, one of them controls the control surfaces as master | | SEC 1: | Flight Control secondary computer #1, each of the two can control all airplane control surfaces in direct law and can become master in case of failure of all primary flight control computers. |
Map (Courtesy Google Earth):
Zoomed in South Atlantic Airways System (Graphics: ASECNA):
Weather Satellite Infrared Image 02:45Z Jun 1st (Courtesy NASA):
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