What happened
On 17 April 2007, a Hal-26 Push Pak, registration G-AVPO, was performing a private flight at Combrook Farm Air Strip near Wellesbourne, Warwickshire. Following a standard approach and touchdown on runway 04, the aircraft began a gentle leftward curve toward a hedge bordering the left side of the runway.
Despite the pilot applying full right rudder and right wheel braking, the aircraft continued to veer left. The left wing eventually struck the hedge, causing the aircraft to swing approximately 270 degrees. The aircraft came to a stop off the runway, facing back toward the landing strip. There were no injuries to the pilot or the single passenger on board, though the aircraft sustained damage to its left wing.
The investigation
The investigation examined the runway conditions and the mechanical state of the aircraft's landing gear. The pilot reported that while the runway surface was initially firm, it became softer toward the left side. Post-accident inspection of the runway revealed wheel tracks indicating that the tailwheel had sunk into a soft patch of ground, leaving a deep, square-sided groove approximately two-thirds the depth of the tyre.
Further examination of the aircraft's tailwheel assembly focused on the connection between the wheel and the rudder circuit. The pilot noted that the tailwheel appeared to be castoring rather than actively steering in response to rudder inputs during the incident. There was no evidence of brake binding during taxi or takeoff, and the left wheel brake functioned normally after the event.
Findings
- The aircraft's tailwheel sank into a patch of soft ground during the landing roll.
- The springs connecting the tailwheel to the rudder circuit were not strong enough to counteract the castoring forces caused by the wheel sinking into the soft surface.
- The pilot's practice of holding the control column back during the ground roll likely contributed to the tailwheel bedding more deeply into the soft earth.