What happened
On 15 June 2003, a student pilot was conducting a solo training flight in a Piper PA-38-112 Tomahawk, registration G-BMVM, near Wycombe Air Park. During the initial approach to the airfield, the pilot noticed unusual vibrations in the controls. This prompted an aborted landing and a continuation of the circuit.
Following subsequent go-arounds due to traffic density, the pilot attempted a third landing. Upon touchdown, the nose of the aircraft dropped significantly further than expected. Fearing a loss of control, the pilot applied full power to attempt another go-around. During this period, the pilot was informed by Air Traffic Control that the nose landing gear had actually detached from the aircraft.
To ensure a safe conclusion to the flight, the Chief Flying Instructor of the training organisation contacted the pilot via radio to provide guidance. The pilot followed these instructions, maintaining the nose up for as long as possible during the final approach. The aircraft eventually touched down on its main wheels, but the nose lowered until the propeller struck the ground, causing extensive damage to the engine and nose cowl. The pilot exited the aircraft without injury.
The investigation
Investigators recovered the lower section of the nose landing gear from the runway. Examination of the cylinder revealed that the component had fractured at a lubrication groove located near the base of the strut housing. The fracture surface showed evidence of both an overload failure and pre-existing fatigue cracking around the outer circumference of the groove.
Records indicated that the nose gear assembly had been installed on G-BMVM in November 2000 and had completed 674 hours of operation. The investigation found that while a requirement for dye penetrant inspections existed in the manufacturer's maintenance manual, a previous error in the manual's insertion had led to confusion. Consequently, the maintenance organisation was unaware of the specific inspection requirement for the cylinder itself.
Findings
- The nose landing gear failed due to a fatigue crack at a lubrication groove at the base of the strut housing.
- The inspection interval based on aircraft hours was inadequate for training aircraft, which experience a higher frequency of landings and higher stress cycles.
- Confusion regarding the manufacturer's maintenance manual meant the necessary inspections had not been performed.
Safety action
- The manufacturer should revise the inspection interval for the nose gear cylinder to account for the high number of landings experienced by training aircraft and communicate this via service information.
- The CAA should consider making the dye penetrant inspection of the nose gear lubrication groove a mandatory requirement.