What happened
On 31 August 2013, a Cozy aircraft, registration G-BXDO, was performing a private flight when the pilot encountered difficulties with the nose landing gear (NLG) while approaching Perth Airport, Scotland. Approximately five miles from the airfield, the pilot attempted to extend the nose gear using the manual cockpit handle. During this process, the handle continued to rotate past the expected stopping point, and the cockpit indicator light failed to signal that the gear was locked. Although a visual inspection through a viewing window suggested the gear was fully extended, an audible warning horn indicated that the mechanism had not reached the downlock position.
Despite multiple attempts to reposition the gear, the mechanism remained immobile. The pilot proceeded with the landing, anticipating a potential gear collapse. After deciding against an approach on the longer runway due to crosswind conditions and visibility concerns, the pilot landed on Runway 27. Upon touchdown, the nose gear slowly collapsed. The pilot managed to steer the aircraft onto the grass, where it came to a halt. There were no injuries to the pilot, but the aircraft sustained damage to the underside of the nose fuselage and the landing gear retractor wheel.
The investigation
Investigators examined the manual worm and gear mechanism responsible for the nose gear's movement. The Cozy design utilizes a manual handle to rotate a worm gear, with an overcentre device intended to lock the leg in place once fully extended. The investigation focused on the physical state of the gear teeth following the impact. It was discovered that a significant number of teeth on the nose gear mechanism's gear had been stripped.
Findings
- The primary cause of the gear failure was damage to the teeth of the nose gear mechanism.
- It is believed that a previous heavy landing had already damaged one or two teeth on the gear, which prevented the nose leg from fully extending into the locked position.
- During the landing at Perth, the landing loads caused the remaining teeth on the mechanism to strip, leading to the collapse of the nose gear.