What happened
On 4 July 2006, a Beech B58 Baron, registration N80HC, was performing a private visual approach to Runway 27 at Guernsey Airport. The pilot had completed all standard landing checks and made what initially appeared to be a normal touchdown. However, as the nosewheel made contact with the runway, a loud bang was heard.
Following this impact, the pilot initiated a go-around. During the climb, the pilot observed the nose gear warning horn sounding and noted that the nose gear green light had extinguished. The pilot determined that the nose leg was unlocked and could not be properly secured. After performing a flyby of the control tower, the pilot entered a holding pattern south of the airport.
To address the landing gear issue, the pilot executed a partial retraction followed by an extension using the manual emergency system. Despite this effort, the nose leg remained in an unlocked position. The pilot subsequently performed another landing on Runway 2 and shut down the engines. During this second landing, as the main gear touched the runway, the engine mixture levers were moved to the cut-off position and the magnetos were turned off. As elevator authority decreased, both propellers struck the ground. The aircraft came to rest in a nose-down position. There were no injuries to the pilot, though the aircraft sustained strikes to both propellers, engine shock loading, and damage to the forward fuselage underside.
The investigation
The AAIB examined the aircraft's components and reviewed photographs of the damaged parts. An engineering investigation conducted by a repair company in the USA revealed that a bolt responsible for locating a drive rod in the operating mechanism had failed. This failure altered the system's geometry, which subsequently caused excessive loads to be applied to the mechanism, leading to further damage.
Findings
- A bolt in the operating mechanism failed, causing a change in geometry.
- This mechanical failure prevented the normal over-centring action from occurring during the gear extension phase.
- The failure of the bolt prevented the nose gear from locking down during the emergency extension procedure.