Incident Summary
On 2 August 2013, an Air France Airbus A320, registration F-HBNI, was involved in a serious incident during approach to Bordeaux Mérignac Airport. The aircraft, operating the third and final leg of the day from Paris Orly, encountered a hailstorm and severe wind shear. The crew executed a go-around as the stall warning activated briefly and the Alpha Floor protection triggered. The aircraft sustained minor damage.
Sequence of Events
During the approach, the captain was the pilot flying and the first officer was the pilot monitoring. The autopilot and autothrust were engaged. Weather briefings had indicated possible thunderstorms, and the crew carried extra fuel for holding. A passenger, qualified as a co-pilot in the same company and a friend of the first officer, occupied the jumpseat for the entire flight with the captain's permission.
While descending, the captain observed a cloud mass and identified a thunderstorm area on the weather radar. The approach was initiated despite the storm cell being on the path. As the aircraft entered the hailstorm, it encountered significant wind shear. The pitch increased to approximately 25° under autopilot, airspeed dropped to 109 knots (VLS minus 27 knots), and the aircraft descended about 200 feet. The crew performed a go-around, during which the stall warning sounded briefly and the Alpha Floor protection activated. After exiting the hailstorm, the crew completed the approach and landed.
Investigation and Findings
The French civil aviation safety investigation authority (BEA) conducted an inquiry. The BEA concluded that the captain's decision to begin the approach with a thunderstorm cell on the trajectory was inappropriate, resulting from a progressive breakdown of crew resource management (CRM). The crew failed to reach a shared decision on the approach path. Spontaneous interventions by the third person in the cockpit and the recollection of a rotation the captain and first officer had flown together three years earlier likely contributed to the CRM deterioration and ineffective threat and error management.
The BEA also noted that the lack of precise weather information from the air traffic controller and repeated messages of clear weather at the airport may have contributed to underestimation of the meteorological risks.
Probable Cause
The BEA identified the probable cause as the captain's inappropriate decision to begin the approach while a thunderstorm cell was on the approach path, resulting from a progressive breakdown of CRM. Contributing factors included interference by a third person in the cockpit, the recollection of a previous shared rotation, and insufficient weather information from air traffic control.
Safety Recommendations
The BEA issued eleven safety recommendations to the European Aviation Safety Agency (EASA) and the French Directorate General for Civil Aviation (DGAC) on topics including third person interference in the cockpit, threat and error management, crew training, wind shear detection training and aids, flight weather information, and stall warning adjustment for aircraft with angle-of-attack protection.