What happened
On September 2, 2008, a Rollason Condor D.62B, registration EI-BXT, departed Abbeyshrule Airfield for a private flight. Shortly after takeoff, while the aircraft was climbing through approximately 300 feet, the pilot noticed a significant right-hand bank. Attempts to correct the attitude using left aileron and rudder inputs were unsuccessful, as the control column felt loose and the aircraft became unresponsive to lateral inputs.
With the aircraft entering an uncontrollable descending bank, the pilot attempted an immediate forced landing. The aircraft struck the ground near a roadway in Colehill, Co. Long and embedded itself into an earth bank. The impact caused the starboard wing to disintegrate and the aircraft to come to rest inverted. Both the pilot and a passenger sustained serious injuries but survived the impact.
The investigation
The AAIU examination of the wreckage focused on the aircraft's flight control systems. Investigators found that the control column torque shaft had separated from the aileron rockshaft. Specifically, the 1/4-inch bolt, slotted nut, and split pin intended to secure these two components together were missing from the assembly and could not be recovered from the crash site.
Technical analysis of the aileron assembly revealed that a plug within the torque shaft had been pushed too far into the bore. This misalignment meant that the holes in the plug were not properly aligned with the holes in the torque shaft during assembly. Metallurgical examination suggested that the bolt likely migrated out of the assembly during the flight, rather than failing due to the impact forces.
Findings
- The primary cause of the accident was the failure of the locking mechanism between the torque shaft and the rockshaft of the aileron control assembly.
- This failure resulted in the pilot losing all aileron control during the initial climb.
- A contributing factor was the possible migration of the bolt from the assembly during the preceding hours of flight, which allowed the control assembly to come adrift.
- The use of four-point upper body restraining harnesses by both occupants was a critical factor in preventing more severe injuries during the impact.