May 2, 2011. Updated June 4, 2011.
The French Bureau of Investigations and Analysis (BEA) announced the recovery of the flight data recorder (FDR) and data/memory component from Air France flight 447, lost with all aboard on June 1, 2009 over the Atlantic Ocean, approximately 600 miles northeast of Brazil.
Data successfully recovered from the FDR will be crucial to the ongoing investigation. In our world of data links, radar data and GPS tracking, airliners don’t mysteriously disappear. Yet that is almost exactly what happened to AF 447, which did not arrive at its destination and was initially reported as overdue. It took several days for investigators to discover a series of automated maintenance-log transmissions from the aircraft, leading to the theory that the Airbus A330 aircraft was lost while trying to navigate through an area of thunderstorms, as it transited the inter tropical convergence zone over the mid-Atlantic Ocean.
In March 2011 a French judge ordered an investigation of Airbus and Air France, which could lead to charges of involuntary manslaughter being brought. Going forward, Air France 447 may be the catalyst for changing the way black boxes work. Instead of retaining the recordings of flight data and crew voices within the crash-resistant devices, future FDRs and CVRs will continuously transmit their data via satellite uplinks, eliminating the time and expense associated with finding black boxes after the fact. In the history of black boxes, 26 so far have been recovered from underwater locations.
On 27 May 2011 the Bureau d’Enquetes et d’Analysis issued an update to the investigation, largely due to the discovery and recovery of data from the two black boxes. Investigators now know that the two co-pilots flying the airplane attempted to work their way through the thunderstorms by reference to the airplane’s weather radar, rather than circumnavigating the area of weather as other flights were doing. Two minutes after making a slight turn to the left and slowing, the BEA report indicates “… the autopilot then auto-thrust disengaged and the PF (pilot flying) said ‘I have the controls’. The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS)”.
One minute and forty-five seconds later, the captain entered the cockpit. The BEA update reports flight conditions as, “The altitude was then about 35,000 ft, the angle of attack exceeded 40 degrees and the vertical speed was about -10,000 ft/min. The airplane’s pitch attitude did not exceed 15 degrees and the engines’ N1’s were close to 100%. The airplane was subject to roll oscillations that sometimes reached 40 degrees. The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds”.
The BEA update concludes: At this stage of the investigation, as an addition to the BEA interim reports of 2 July and 17 December 2009, the following new facts have been established:
- 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.