What happened
On 10 March 2006, an BAe Avro RJ85, registration OO-DJN, operated by SN Brussels Airlines, experienced a landing gear malfunction shortly after departing Gothenburg/Landvet and attempted an emergency return. During the initial takeoff, the crew noted that the red warning lamp indicating the nosewheel was not retracted and locked failed to extinguish. Subsequent attempts to cycle the gear and activate the emergency extension system were unsuccessful, and the cockpit indications failed to confirm the nosewheel was down and locked.
In an effort to verify the gear position, the crew performed a low-altitude fly-by parallel to runway 03, allowing ground personnel to visually inspect the aircraft. Based on feedback from ground staff suggesting the gear appeared extended, the pilots proceeded with the landing. The aircraft touched down smoothly on its main gear, but approximately 17 seconds into the ground roll, the nosewheel gear folded forward. The nose of the aircraft struck the runway, causing a 300-meter slide accompanied by sparks and smoke. All 32 persons on board survived the incident, though the aircraft sustained substantial damage.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the aircraft's maintenance history, the flight recorders, and the mechanical components of the landing gear. The investigation focused on why the nosewheel locking mechanism failed to engage despite the crew's attempts to use vertical G-forces to force the gear into position. Technical examinations of the nosewheel gear and the grease-nipple components were also conducted.
Findings
- The primary cause of the accident was the seizure of the nosewheel locking mechanism.
- This seizure was directly caused by a blocked grease nipple, which prevented sufficient lubrication of the mechanism and led to it jamming.
- The crew's decision to land based on visual confirmation from the ground was based on an incomplete assessment of the gear's locked status.
- During the emergency evacuation, a cabin crew member encountered difficulty securing a rear left door in the fully open position due to the aircraft's tilted angle.
Safety action
- The SHK recommended that the Swedish Civil Aviation Authority investigate the need for specific regulations regarding low-altitude fly-bys used for technical inspections.
- A recommendation was made to EASA to ensure that aircraft certification requires emergency exits to be capable of being secured in the open position, even when the aircraft is at an abnormal tilt.