Could the recovery of Flight AF 447’s onboard recorders explain the mysterious Air France accident that killed 228 passengers and crew?
Two flight recorders and other parts from an Air France airliner that crashed en route from Rio de Janeiro to Paris have been recovered from the bottom of the Atlantic almost two years after the accident, which led to the loss of 228 passengers and crew.The instruments have been delivered under tight security to the French air accident investigation office, BEA, where officials hope it will be possible to recover data that will shed light on why the Airbus A330-200 came down. The crew had not reported any problems with the flight, and no emergency signal was received before the aircraft disappeared.
It is known that Flight AF 447 encountered a severe thunderstorm, but no-one has come up with a satisfactory explanation as to the likely cause of the aircraft’s loss. Investigations have been hampered by the lack of tangible evidence.
When the alert was raised on 1 June 2009 there was an immediate air and sea search for survivors, but it was not until five days later that bodies and debris were seen floating 70km north of the aircraft’s last known position (LKP). A search along the most likely flight path could not detect any acoustic signals that would have indicated the presence of beacons designed to maintain transmissions for 30 days, and two further underwater searches in 2009 and 2010 also failed to find any sign of the plane.
The bodies, engines and other parts were finally located and identified in April this year as part of an operation to survey areas that had not previously been covered, using robotic underwater vehicles fitted with sonars and photographic equipment and capable of operating down to a depth of 6,000m. That expedition was led by a team from the Woods Hole Oceanic Institute in the US under BEA authorisation.
With the success of the fourth search, BEA immediately set a new mission in train in an attempt to locate and recover the flight data recorder (FDR) and cockpit voice recorder (CVR).
The cable vessel Ile de Sein, operated by Alcatel-Lucent and Louis Dreyfus Armateurs, was sent to the search area equipped with another remotely operated vehicle (ROV), a Remora 6000 from Phoenix International. On board was a team of six air accident investigators (four from BEA and one each from Brazil and the UK’s AIIB), experts from Airbus and Air France, an American specialist in sonar imagery who had taken part in the Phase 4 search and a psychologist. There was also a team from the French judicial authorities, and nine ROV operators.
During the crossing the investigators continued analysing the earlier photographs to help them localise the flight recorders, and began planning the operational procedures aimed at recovering the pieces that were likely to prove useful.
The Remora 6000’s first operational dive in the search area, on 27 April, lasted over 12 hours and had an early success in finding the chassis of the flight data recorder, surrounded by debris from other parts of the plane, though it was without the crash survivable memory unit (CVMR) that holds the data.
Further dives identified other parts, but no lifting operations were carried out as the priority was to find the CVMR and the cockpit voice recorder. The first breakthrough came on 1 May with the discovery of the missing memory unit. This was raised and lifted onto the Ile de Sein. Then the next day the CVR was also recovered.
Both items were placed in locked cases under judicial seal, and the French Navy sent a patrol boat at BEA’s request to transport them to Cayenne in French Guyana, from where they were transferred by air to Paris, escorted by the chief BEA investigator, his Brazilian counterpart and an officer of the French judicial police.
Recovery of aircraft parts is continuing, with one engine and the avionics bay, containing onboard computers, having been raised at the time of writing.
A French judge has ruled that any bodies should be left undisturbed, to preserve their dignity and to avoid distress to their relatives.
Both Airbus CEO Tom Enders and Air France chief executive Pierre-Henri Gourgeon have said they hope data from the flight recorders will answer unresolved questions and lead to an understanding of how the accident occurred.