What happened
On 22 August 2007, a Piper PA 31-350 operated by Nelair Aviation Services was conducting a domestic commercial charter flight from Kruger Mpumalanga International Airport (FAKN) to Sabi Sands. Shortly after takeoff, the pilot attempted to retract the landing gear but noticed the "gear unsafe" red warning light remained illuminated. After an unsuccessful attempt to recycle the gear, the pilot utilized the emergency hand pump to extend the undercarriage. While this successfully locked the main landing gear, a visual inspection via the engine cowling mirror revealed the nose landing gear was stuck at an approximate 45-degree angle.
The pilot diverted to Nelspruit Aerodrome to consult with maintenance personnel before deciding to return to FAKN for a forced landing. Upon touchdown on Runway 05, the partially extended nose landing gear collapsed. The aircraft' and nose section slid along the runway surface, causing substantial damage to the airframe and propellers. Although the occupants were momentarily hindered by doors that were difficult to open due to fuselage distortion, all zero injuries were reported as the crew and five passengers evacuated safely.
The investigation
Investigators examined the wreckage and the aircraft's hydraulic system to determine why the nose gear failed to lock. The inspection of the nose wheel bay revealed that a hydraulic pressure door open hose (P/N 17766-02) had been punctured by a screw. This puncture caused a hydraulic leak, which depleted the system pressure necessary to fully extend the nose gear. It was noted that the hose may have been long enough to make contact with the screw during normal operation.
Additionally, the investigation looked into the evacuation process, noting that passengers struggled to exit via the emergency and cabin doors. The investigation also reviewed the operator's records, noting discrepancies in the aircraft logbook regarding operating hours and the lack of immediate air ticket availability for the passengers.
Findings
- The primary cause of the gear failure was a hydraulic leak caused by a screw puncturing the door open hose.
- The loss of hydraulic pressure prevented the nose landing gear from reaching the down and locked position.
- The nose gear collapse during the landing roll resulted in substantial damage to the Piper PA 31-350.
- Structural distortion of the fuselage following the impact made the aircraft doors difficult to operate during evacuation.