Air France Flight 447 Final Report

The Air France 447 crash investigation: a nearly bungled case of project management

On June 1, 2009, Air France Flight 447 from Rio de Janeiro, Brazil, to Paris, France, fell into the Atlantic Ocean northeast of Brazil. Two years later, the May 4, 2011 issue of the New York Times magazine included a fascinating story about this crash and the two years of investigation which had followed the disaster:

http://www.nytimes.com/2011/05/08/magazine/mag-08Plane-t.html?pagewanted=1&_r=1

This reporting involved a lot of unanswered questions which were dealt with a year later when, on July 5, 2012, the final report was issued by the French air safety bureau (BEA) as summarized below.

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On 5 July 2012, the BEA released its final report on the accident. This confirmed the findings of the preliminary reports and provided additional details and recommendations to improve safety. According to Report Summary, Section 4, the accident resulted from the following succession of major events:

• the pitot tubes were obstructed by ice crystals, causing loss of airspeed measurements;
• the autopilot automatically disconnected, switching to "alternate law";
• the crew was surprised at losing airspeed indication while in high-altitude cruise through turbulence;
• the crew made inappropriate control inputs (over-handling) that destabilized the flight path;
• the crew lacked understanding of the approach to stall;
• the crew failed to recognize that the aircraft had stalled and consequently did not make inputs that would have made it possible to recover from the stall.

These events resulted from the following major factors in combination:

• the lack of effective feedback mechanisms made it impossible to identify and remedy the repeated non-application of the procedure for inconsistent airspeed, and to ensure that crews were trained in handling icing of the Pitot probes and its consequences;
• the crew lacked practical training in manually handling the aircraft both at high altitude and in the event of anomalies of speed indication;
• the two co-pilots' task sharing was weakened both by incomprehension of the situation at the time of autopilot disconnection, and by poor management of the startle effect, leaving them in an emotionally charged situation;
• the cockpit lacked a clear display of the inconsistencies in airspeed readings;
• the crew did not respond to the stall warning, whether due to a failure to identify the aural warning, to the brevity of the stall warnings that could have been considered spurious, to the absence of any visual information that could confirm that the aircraft was approaching stall after losing the characteristic speeds, to confusing stall-related buffet for overspeed-related buffet, to the indications by the Flight Director that might have confirmed the crew’s mistaken view of their actions, or to difficulty in identifying and understanding the implications of the switch to alternate law, which does not protect the angle of attack.

http://en.wikipedia.org/wiki/Air_France_Flight_447

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Train for the ‘startle effect’:
Air France 447 InvestigationBy Aimee Turner, July 6, 2012

The crew of flight AF447 was in a state of almost total loss of control of the situation, according to the air accident chief leading the investigation into the downing of the Air France A330 jet in June 2009.

Read The Air France AF447 Dossier

French accident investigation chief Alain Bouillard explained how malfunctioning speed sensors initially triggered the disconnection of the autopilot at which point the pilots failed to react correctly as the aircraft started to stall and lose altitude.

Investigators said they had found it hard to understand why the crew failed to respond to the repeated stall alarms saying this could have been explained by the crew not understanding the alarm’s sound or that it was too quiet..

"The pilots stuck to what they do usually… When you lose awareness of the situation you hang on to what you’re used to doing," said Bouillard.

The final accident report – which made 25 new safety recommendations in addition to the 16 lodged in an earlier interim report -- stressed the importance of adequate training so that pilots have a better knowledge of flight mechanics in the event of an unusual situation.

"The startle effect played a major role in the destabilisation of the flight path and in the two pilots understanding the situation. Initial and recurrent training as delivered today does not promote and test the capacity to react to the unexpected. Indeed the exercises are repetitive, well known to crews and do not enable skills in resource management to be tested outside of this context," the report stated.
"All of the effort invested in anticipation and predetermination of procedural responses does not exclude the possibility of situations with a ‘fundamental surprise’ for which the current system does not generate the indispensable capacity to react."

It recommended that the organisation charged with overseeing European pilot training – the European Aviation Safety Agency – modify rules in order to ensure better fidelity for simulators in reproducing realistic scenarios of abnormal situations, in addition to introducing the effects of surprise and situations with a highly charged emotional factor.

"If the BEA thought that this accident was only down to the crew, we would not have made recommendations about the systems, the training, etc. Which means that this accident could no doubt have happened to other crews," said the head of the French air accident investigation bureau Jean-Paul Troadec.

Air France, in a statement, said the final report demonstrated that the crew acting according to the information supplied by the instruments and onboard systems, and the aircraft’s behaviour as observable from inside the cockpit, adding that the crew’s readings of the instruments, alarms, aerodynamic sounds and aircraft vibrations ‘did not allow them to apply the appropriate actions’.

http://www.airtrafficmanagement.net/2012/07/train-for-startle-effect-af447-investigation/