What happened
On 14 August 2002, a Gill SA Pulsar, registration G-BSFA, was performing a private flight from Gloucestershire Aerodrome, Staverton. During the takeoff roll, as the aircraft reached rotation speed, the nose wheel assembly became detached from the strut. The occupants were initially unaware of the separation and only learned of the issue after being alerted by a radio message from another aircraft preparing to depart behind them.
Following the notification, the pilot orbited the airfield for approximately 20 minutes while emergency services were summoned. During this period, the crew performed a low approach and a go-around, which allowed ground observers to confirm that the nose wheel and fairing were indeed missing. After a second approach, the pilot prepared the aircraft for landing by switching off the magnetos and securing the fuel and battery. Upon touchdown, the pilot attempted to keep the nose off the runway for as long as possible, avoiding wheel braking. However, the nose leg eventually settled onto the runway and slid for roughly 30 metres before digging into the surface, causing the aircraft to stop abruptly. There were no injuries to the two occupants, though the aircraft sustained damage to the nose leg and the floor area behind the firewall.
The investigation
The investigation involved a metallurgical analysis of the failed nosewheel pivot pin and the recovered nosewheel assembly. Investigators also examined an intact strut and pin from the same aircraft that had been replaced shortly after the aircraft's construction due to a bent pin.
Testing of the failed pin revealed a fatigue fracture located near the upper face of the collar. The examination showed multiple initiation sites on both the front and rear surfaces of the pin's circumference, as well as secondary sites on the sides. This pattern indicated that the pin had been subjected to reverse bending loads while the nosewheel was not in a straight-ahead position. Analysis of the replacement strut provided further evidence of fatigue, showing cracks caused by tension and bending mechanisms, even though that specific component had only been in service for a short period.
Findings
- The detachment of the nosewheel was caused by a fatigue fracture of the pivot pin.
- The failure resulted from typical in-service loads rather than a single heavy landing event.
- The design of the nose landing gear installation makes it difficult to perform reliable inspections to detect cracks in the pin.
- The aircraft had completed over 300 flying hours, which is relatively high for this specific type on the UK register.