What happened
On 15 June 2004, a Cessna 310, registration N310QQ, was performing a private flight when it experienced a landing gear failure at Elstree Aerodrome, Hertfordshire. The pilot initiated a standard approach to Runway 26 under wind conditions of 330°/06 kt. Prior to touchdown, the pilot confirmed that the landing gear indicators showed the gear was down and locked, and full flaps were visually verified.
Although the initial touchdown was smooth, the 'Gear Unsafe' warning horn activated during the landing roll. The pilot observed that the green indicator for the left main landing gear had extinguished, replaced by a red 'Gear Untended' light, while the nose and right main gear remained secure. Shortly thereafter, the left main landing gear collapsed. This caused the aircraft to slew toward the left side of the runway, eventually coming to a stop in the grass. There were no injuries to the pilot or the passenger, though the aircraft sustained damage to the left main landing gear and the left side of the airframe.
The investigation
The investigation was based on the aircraft accident report provided by the pilot and a metallurgical analysis of the failed components. Investigators examined the structural integrity of the landing gear assembly to identify any underlying mechanical issues.
Findings
- A metallurgical examination of the failed parts revealed that the damage was the result of a single-event overload force.
- There was no evidence of fatigue, corrosion, or any manufacturing defects present in the components.
- It was noted that the left main landing gear may have been slightly out-of-rig, which could have allowed the side brace to unlock after the aircraft encountered a bump on the runway surface.