What happened
On April 5, 2000, an Air Liberté Fokker 100, registration F-GNLI, was preparing for a scheduled flight from Paris Orly to Bordeaux Mérignac. During taxiing, the crew noted a hydraulic tank pressure warning on the multifunction display unit (MFDU). After consulting the Minimum Equipment List (MEL), the crew decided to proceed toward the departure point. Shortly after lining up on runway 08, a second warning regarding the hydraulic system pump appeared, but the crew determined the aircraft was still within technical tolerances and proceeded with the takeoff.
At 09:57 UTC, the aircraft began its takeoff roll. As the aircraft reached approximately 80 knots, just prior to rotation, the forward left passenger door opened. The flight crew continued the takeoff roll and immediately declared a Mayday. Following instructions from Orly Tower, the crew performed a visual circuit to the south and returned to land on runway 08. The aircraft landed at 10:02 UTC, with emergency services and medical personnel on standby. There were no fatalities or injuries among the 38 passengers and 5 crew members.
The investigation
The investigation focused on the mechanics of the door's locking and detection systems. Investigators examined the kinematic movement of the locking mechanism, which utilizes two pivoting hooks at the top of the door frame and four metal cylinders that extend into the door to provide redundancy. The investigation also reviewed the cockpit alarm systems and the status of the door's handle and detection sensors.
Flight data and cockpit voice recordings revealed that a cabin crew member had noticed a strange noise during the takeoff roll and attempted to check the door. The investigation established that the door had become unlatched, leading to its spontaneous opening under aerodynamic forces. The aircraft sustained damage to the door, which required replacement, and the fuselage sustained minor damage from impacts caused by components of the door being torn away during the incident.
Findings
- The primary cause of the incident was the spontaneous opening of the forward left passenger door during the takeoff roll.
- The door's locking mechanism failed to maintain a secure state during the high-speed phase of the takeoff.
- The crew's decision to continue the flight despite earlier hydraulic warnings was permitted by the MEL, though the door failure was an independent mechanical event.
- The aircraft's structural integrity was compromised by the loss of door components, necessitating an emergency landing procedure.