Aircraft Information
The aircraft involved was a Jabiru UL, registration G-OMHP, with one Jabiru Aircraft Pty 2200A piston engine. It was manufactured in 2000 and was being operated on a private flight with one pilot and one passenger on board.
Accident Details
On 23 July 2010 at 1645 hrs, the pilot, who held a National Private Pilot’s Licence and had 68 hours total flying experience (18.5 on type), had rigged the aircraft prior to an inspection by a Light Aircraft Association (LAA) inspector. While awaiting the inspector, the pilot decided to conduct a 'practice takeoff' – an accelerate-stop manoeuvre on the grass runway – with no intention of becoming airborne. The aircraft accelerated with zero flap selected. At approximately 50 kt, it began to drift to the right. The pilot reduced power and applied brakes, but this appeared to exacerbate the situation. The aircraft ran onto rough ground on the right side of the runway, spun around, and the left wing contacted an earth bank and a fence. During the event, the nose leg collapsed and the propeller struck the ground. The aircraft came to rest with the left wing partially torn off and its wing strut separated near the fuselage attachment. The occupants were uninjured and exited via the doors.
Examination Findings
An LAA inspector, upon arriving at the scene, noted that the right flap was hanging in its fully down position. It was discovered that a pin connecting the right flap to its operating linkage in the fuselage had become disengaged because a 'Terry-clip' type safety pin was missing. The aircraft was taken to a repair organisation, where the brake system components were examined and showed no evidence of roughness or any feature that could have caused the right brake to grab or drag. The nose landing gear leg was examined and found to have sustained overload failures consistent with detachment during the accident, not as an initiator.
Discussion
Although the pilot had selected zero flap, the absence of the right flap safety pin could have caused the flap to stream in an approximate zero position. This would be unlikely to produce significant directional control difficulties, though some loss of lift was possible if the flap rigging allowed it to extend beyond normal retracted position. However, there was insufficient evidence to determine whether the missing safety pin was a factor in the accident. The event emphasised the necessity of a thorough pre-flight inspection after rigging any aircraft.