What happened
On 28 March 2017, an Airbus A318, registration F-GUGB, operated by Air France, performed a takeoff at Paris Charles-de-Gaulle using maximum TOGA thrust for training purposes. Because the aircraft was light, the crew anticipated significant acceleration. During the climb, the pilot flying applied a high nose-up input, causing the pitch attitude to reach 24.6°. This triggered the nose-up attitude protection and subsequently the ALPHA-FLOOR protection due to sidestick deflection exceeding 14°. The crew observed a TOGA LK message but did not notice the brief ALPHA-FLOOR alert. They subsequently reset the auto-thrust and continued the flight without further incident.
Two days later, on 30 March 2017, the same crew operated a ferry flight in an Airbus A321, registration F-GTAT, from Toulouse to Paris. Seeking to understand the previous incident, the crew intentionally repeated the takeoff with TOGA thrust. During the climb, the pilot flying again applied significant nose-up inputs, reaching a 24° attitude and triggering the ALPHA-FLOR protection again.
Later in the flight, while climbing through FL100, the crew performed a voluntary, steep maneuver. The aircraft accelerated to 350 kt in level flight before pitching up to 27°, resulting in a vertical speed exceeding 13,000 ft/min. This rapid climb triggered a TCAS conflict alert for a nearby aircraft at FL400 and caused the air traffic controller to request a reduction in climb rate.
The investigation
The BEA examined flight parameters and crew statements to determine why the flight envelope protections were activated. The investigation focused on the criteria for ALPHA-FLOOR activation, specifically the secondary trigger involving sidestick deflection. The investigators also reviewed the crew's decision-making process regarding the intentional repetition of the takeoff conditions and the subsequent high-rate climb maneuver during the ferry flight.