What happened
On 14 May 2018, a Piper PA-34-200T Seneca II, registration G-RVRB, was conducting a training flight at Sleap Aerodrome in Shropshire. The pilot performed a stable and normal approach, with all landing gear indicators confirming the gear was down and locked. However, roughly two seconds after the aircraft touched down on the runway, the nose landing gear collapsed. The aircraft subsequently came to a stop on the runway. There were no injuries to the two crew members on board. The incident resulted in damage to the propellers and fuselage, as well as shock-loading of the engines and damage to the nose landing gear.
The investigation
The AAIB examined the mechanics of the nose landing gear system, which is a forward-retracting design. In this configuration, the gear is secured in the extended position by drag links held in an overcentre position via a spring-loaded downlock link. Following the accident, a maintenance agency inspected the assembly and discovered that the downlock link attachment bolt had become distorted. This distortion prevented the drag link assembly from remaining in the overcentre position. After the installation of a new bolt, the drag links were able to remain locked when overcentred.
Findings
- The nose landing gear collapsed due to the failure of the downlock link attachment bolt to maintain the overcentre position.
- The aircraft was compliant with the FAA Airworthiness Directive regarding periodic inspections of the nose landing gear installation.
- The operator suggested that the distortion of the bolt was likely caused by the aircraft having been subjected to one or more unreported heavy landings.