What happened
On 19 June 2008, a Yak-52, registration G-CBOZ, was conducting a private flight when the pilot identified a malfunction in the landing gear system. Upon arriving at Headcorn, the pilot set the landing gear to the DOWN position. While the nose and right main landing gear showed green 'down and locked' indications, the left main landing gear failed to provide a corresponding indication.
To verify the status of the gear, the pilot performed a low flypast for ground personnel. Following this, the pilot executed several landing gear retractions and extensions, along with high-g manoeuvres, and attempted to use the emergency extension system for the right main landing gear. Despite these efforts, the left main landing gear remained unextended. The pilot then decided to perform a controlled wheels-up landing. After circling the airfield to reduce fuel weight, the aircraft touched down on a long grass area adjacent to Runway 29. The aircraft travelled approximately 100 metres before coming to a stop. There were no injuries to the pilot.
The investigation
The investigation focused on the mechanical failure of the left main landing gear. Examination of the aircraft revealed a broken propeller and evidence that the engine may have been shock-loaded. Crucially, investigators discovered a broken gear uplock release catch. Furthermore, bird remains were found embedded within the left gear uplock mechanism. The pilot noted that the bird strike likely occurred during the period of high-g manoeuvres and gear cycling.
Findings
- The left main landing gear failed to extend because the uplock mechanism was obstructed.
- Bird remains found in the left gear uplock mechanism prevented the normal operation of the gear.
- The pilot's decision to land wheels-up was a deliberate response to the confirmed gear failure.