Common Themes

Organizational Lapses

It became clear during the investigation that Air France was not aware of the specific features of the VNAV system and its intended behavior during approaches. Nor were they aware that the mode needed to be disengaged at the missed approach point. Though Boeing had provided information related to system usage and recommended practices, specific information about system response if engaged beyond the missed approach point was not clearly provided. As a result, Air France had not provided training to its crews, and the accident crew was not aware that system disengagement was required prior to landing.

Human Error

When the auto-throttles advanced to go-around power, they remained at the go-around position for nearly 20 seconds before the pilot flying manually restrained them, and then retarded them to the idle position. The auto-throttles were never disconnected, requiring the pilot to continue holding them at idle while continuing the landing. If the auto-throttles had been disconnected, thereby cancelling the command to advance to go-around thrust, a successful landing would have been possible.

Flawed Assumptions

The flight crew assumed that it was acceptable to continue a VNAV approach all the way to touchdown. The system was not intended to remain engaged beyond a predetermined point in the approach (missed approach point). As a result, when reaching that predetermined point, the system commanded a go-around.

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