A French court on Monday acquitted Airbus and Air France of involuntary manslaughter charges stemming from the 2019 crash of Flight AF447 into the Atlantic Ocean on a trip from Rio de Janeiro to Paris. All 228 occupants died when the Airbus A330-200 crashed at night while negotiating a region with heavy thunderstorm activity.
A three-judge panel ruled that the state did not produce evidence of any direct connection between the companies’ actions and the crash. The final verdict did not come unexpectedly, as prosecutors recommended acquittal after not finding the companies criminally liable.
The Paris Criminal Court’s October 22 summary of the prosecution case centered on suggestions that Airbus did not react adequately or quickly enough to repeated reports of problems with the pitot probes that collect airspeed data. A probe by French air accident investigation agency BEA (Bureau d’Enquetes et d’Analyses) had confirmed previous discussions between Airbus and Air France on the issue, while also highlighting an apparent failure by pilots to initiate unreliable indicated airspeed procedures and confusion about the functioning of the autopilot. Essentially, the AF447 flight crew, who collectively accrued more than 20,000 flight hours of experience, had not grasped that the A330 had stalled.
The case weighed allegations of technical failings in the A330 design against crew errors and possible shortcomings in training and operational procedures. Investigators determined that the accident resulted from a chain of events brought on by a lack of valid airspeed data after all three of the aircraft’s pitot tubes froze.
In its final report issued on July 5, 2012, the BEA explained most—but not all—of the pitch-up inputs by the pilot flying the aircraft during the last minutes of the flight. The report said the pilot kept pulling the stick back, which caused the Airbus A330 to stall and prevented recovery.
A major finding in the final report concerned the flight director, which normally displays symbology on the pilots’ primary flying displays that give guidance on control inputs to reach a desired steady-state flight path. After the autopilot and autothrottle disengaged, as the flight control law switched from normal to alternate, the flight director’s crossbars disappeared. But they then reappeared several times. Every time they were visible, they prompted pitch-up inputs by the pilot flying, investigators determined.
The BEA acknowledged that the pilot might have improperly followed flight director indications during the stall. However, it appeared the crew did not realize that the airplane had stalled, and the successive disappearance and reappearance of the crossbars reinforced this false impression, the investigators suggested.
BEA investigators have suggested several factors that might explain why the crew did not react to the stall alarm, despite its sounding more than 70 times as the Airbus A330-200 descended at up to 11,000 feet per minute, at angles of attack ranging between 35 and 45 degrees.
One explanation centered on the possibility that the crew might have thought the buffeting, aerodynamic noise, and even an acceleration cue on the primary flight display were symptoms of overspeed. The report questions whether the crew even heard the alarm. When it sounded, the pilots already had become highly stressed and perhaps so absorbed with the onslaught of visual information that their brains failed to process the aural cues, suggested Sébastien David, head of the investigation's human-factors group at the time.
Moreover, the report continues, the pilots received “very little [exposure] to stall situations” in their training, hence a lack of familiarization with the stall warning and the actions it should have triggered.
The investigators made it clear that from the start the crew should have followed a procedure called “unreliable indicated airspeed,” which involves disconnecting the flight director. They also concluded that the still-connected flight director behaved in a manner not specific to the A330.