What happened
On 11 March 2017, an Airbus A340-313E, registered F-GLZU, operated by Air France, was performing a scheduled commercial flight from Bogotá (Colombia) to Paris (France). The aircraft was carrying 268 passengers and 13 crew members.
During the night takeoff from runway 13R, the crew applied 5-0% thrust on the brakes before transitioning to full takeoff thrust. While the crew had calculated performance for a wet runway, the rotation process was significantly slower than expected. The pilot flying initiated rotation at the calculated speed, but the aircraft's rotation rate was insufficient. As a result, the main landing gear did not leave the ground until the aircraft was only 140 meters from the threshold of the opposite runway. The aircraft crossed the opposite runway threshold at a radio altimeter height of approximately 4 feet, narrowly clearing the first ILS antennas at a vertical distance of only 12 feet.
The investigation
The investigation was initiated after the crew filed an Air Safety Report noting the unusually long takeoff. The BEA analyzed flight data from the Direct Access Recorder (DAR) and conducted various technical verifications. The investigation examined takeoff performance models, rotation techniques used by crews, and the manufacturer's documentation. The BEA also looked into the discrepancy between the certified performance models and the actual rotation rates achieved during flight operations.
Findings
- The primary cause of the serious incident was insufficient nose-up inputs from the pilot flying, which led to a rotation rate lower than the 3°/s used in certified performance models.
- This slow rotation increased the takeoff distance by 424 meters compared to the certified theoretical distance and required safety margins.
- The rotation technique applied by the crew, following the recommended 2/3 backward deflection, was not sufficient to achieve the necessary rotation rate under the specific operational conditions.
- There was a lack of identified discrepancy between operational rotation rates and certified performance models due to a lack of monitoring and air safety reports regarding this specific parameter.
Safety action
Following the incident, several safety measures were implemented by Air France, Lufthansa, Airbus, and EASA. The BEA issued seven safety recommendations to EASA regarding the certification of takeoff performance, the management of risks related to long takeoffs, and the enhancement of flight analysis programs to monitor takeoff performance indicators.