What happened
On August 2, 2013, an Air France Airbus A320, registration F-HBNI, was performing its final flight leg of the day, arriving from Paris Orly to Bordeaux Mérignac. During the approach, the flight crew decided to fly through a zone of thunderstorm activity identified on the onboard weather radar.
As the aircraft entered a cell containing hail, it encountered severe windshear. The aircraft's pitch increased to approximately 25 degrees while under autopilot, and the airspeed dropped to 109 knots, which was 27 knots below the minimum steady speed (VLS). The aircraft descended by roughly 200 feet before the crew executed a go-around. During this period of turbulence, a brief stall warning was triggered, and the aircraft's "Alpha Floor" protection activated. The crew continued the approach once the aircraft had cleared the hail cell.
The investigation
The BEA investigation focused on the decision-making process and the breakdown of Crew Resource Management (CRM). Investigators examined the flight data, cockpit voice recordings, and the presence of a third person in the cockpit—a passenger who was also an Air France co-pilot. The investigation also reviewed the meteorological information provided by Air Traffic Control and the crew's use of the onboard radar.
Findings
- The primary cause of the incident was the inappropriate decision by the commander to initiate the approach while a thunderstorm cell was directly on the approach path.
- A progressive breakdown in CRM occurred; the crew failed to reach a shared decision regarding the arrival trajectory.
- The presence of a third person (the passenger/co-pilot) in the cockpit interfered with effective communication and contributed to the destabilization of the crew's management of the flight.
- The crew's Threat and Error Management (TEM) was ineffective, as they failed to recognize the specific risk of hail, likely due to misinterpreting the weather radar's red echoes as heavy rain rather than hail.
- Communication between the pilot flying and the pilot monitoring was disrupted by technical and non-professional discussions involving the third person, which isolated the commander.
- The crew's decision-making was inconsistent, with the commander relying on naturalistic experience while the co-pilot followed a more normative approach, leading to a lack of consensus on the flight path.