What happened
On 26 April 2009, a Glasair RG, registration G-BKHW, was performing a private flight from Humberside to Cranwell Airfield. During the initial takeoff roll at Humberside, the aircraft experienced a pilot-induced yaw oscillation. Although a more experienced pilot took control, the left wheel made contact with the runway and the right wheel reportedly struck a runway edge light.
While en route, the crew observed a landing gear in-transit indication. Upon arriving at Cranwell, the pilot attempted to cycle the gear, but only the nose and left gear legs showed green indications. After communicating with Air Traffic Control and receiving confirmation from another aircraft that the right gear was not fully extended, the pilot performed a landing on Runway 19. During the landing rollout, the right wing dropped, causing the aircraft to slew to the right and resulting in the collapse of the nose gear. Both occupants escaped without injury.
The investigation
Investigators examined the aircraft's hydraulic and mechanical systems to determine why the gear failed to deploy. The inspection revealed that a hydraulic fitting on the right landing gear actuator had fractured, leading to a loss of hydraulic fluid. This fracture rendered the primary landing gear operating system inoperative.
Furthermore, the investigation focused on the failure of the emergency nose gear deployment system. The nose gear utilizes a gas spring to force the gear down during emergency use; however, this component was found to be ineffective. The piston of the gas spring had suffered from corrosion and seal chafing, which allowed the gas to leak out.
Findings
- A fractured elbow fitting on the right landing gear actuator caused the loss of hydraulic fluid.
- The failure of the emergency nose gear deployment system was caused by a leaking gas spring due to a corroded chrome piston and a chafed seal.
- The right landing gear leg was bent approximately 2 degrees backwards, causing the tyre to overlap the wheel.
- The pilot noted that the takeoff roll should have been aborted before the yaw oscillation developed.