What happened
On 28 November 2004, a Boeing 737, registration PH-BTC, was operating a scheduled passenger flight from Amsterdam-Schiphol Airport to Barcelona Airport. During the takeoff phase at Amsterdam, the aircraft experienced a bird strike in the area of the nose landing gear during rotation. While the flight crew notified Air Traffic Control of the event, no abnormal indications were noted in the cockpit, and the flight continued to its destination.
Upon arrival at Barcelona, the aircraft performed its landing roll on runway 2-5R. As the nose wheels made contact with the runway, the aircraft began deviating to the left. The flight crew attempted to correct the trajectory using right rudder, brakes, and the nose wheel steering tiller, but the deviation could not be arrested. The aircraft exited the runway through unprepared terrain to the left of the runway axis, eventually coming to a stop approximately 107 meters from the runway axis near a drainage canal. An emergency evacuation was conducted, resulting in 5 passengers sustaining minor injuries.
The investigation
The investigation examined the mechanical state of the nose wheel steering system, the impact of the bird strike, and the maintenance history of the aircraft. Investigators analyzed the flight recorders, including the Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR), and performed a visual inspection of the wreckage. The investigation also reviewed the condition of the runway strip at Barcelona, which was undergoing construction works at the time of the accident.
Findings
- The primary cause of the excursion was a fracture of a cable within the nose wheel steering system. This fracture caused the nose wheels to rotate to the left upon touchdown, inducing the leftward veer.
- The bird strike during takeoff at Amsterdam provided the initial impact that contributed to the cable failure.
- The cable was found to be severely worn locally, a condition caused by the incorrect application of grease during previous maintenance procedures.
- The aircraft's ability to maintain the runway was further compromised by the condition of the runway strip, which was affected by ongoing airport construction.
- Despite the crew's experience, the rapid deceleration and the nature of the steering failure prevented them from recognizing and correcting the cause of the deviation in time.