What happened
On 13 October 2006, a Pulsar aircraft, registration G-BUDI, was performing a private flight at Popham Airfield. The pilot executed a standard approach and landing on Runway 08. During the flare, the pilot applied back pressure to the control column to ensure a gentle touchdown on the grass surface. However, as the nose landing gear made contact with the ground, the nose gear failed. This caused the aircraft to pitch forward, ultimately coming to rest on its propeller. The pilot, who was the sole occupant, exited the aircraft without any injuries.
The investigation
Investigators examined the aircraft's nose landing gear assembly and the engine mount. The nose gear on this model features a thick-walled square tube with a castoring wheel assembly. A drag brace connects the top of this strut to a longitudinal member of the engine mount assembly. The investigation focused on the longitudinal engine mount tube, specifically at the point where it was welded to a rear lateral bracing tube.
Metallurgical analysis of the failed component revealed that the tube was made of ferro-magnetic steel. While the fracture face showed significant mechanical damage caused during the accident, evidence of the original failure was present. The examination identified multiple fatigue initiations occurring along the top edge of the tube, specifically at the site of the weld.
Findings
- The failure of the longitudinal engine mount tube occurred at the weld location connecting it to the rear lateral bracing tube.
- Fatigue damage induced by cyclic bending from normal operating loads was the primary cause of the separation.
- The investigation noted that the failure was consistent with typical in-service loads rather than a single heavy landing event.