What happened
On 21 August 2002, a Stern ST80, registration G-BWVI, was involved in an accident at the Long Mynd Gliding Site in Shropshire. The incident occurred at approximately 1757 UTC. During the landing, the nose wheel pivot on the end of the nose leg fractured.
The investigation
Following the initial accident report, the aircraft underwent repair work. During this process, the owner identified new information that was not previously known at the time of the accident.
Upon weighing the aircraft after repairs, it was determined that the empty weight was 265 kg, which was significantly higher than the 237 kg listed in the weight and balance schedule used by the pilot. Because no new modifications had been added to the aircraft since its manufacture, investigators concluded the original weight had been recorded incorrectly. This discrepancy meant the aircraft's operating weight may have exceeded its maximum all-up weight during the flight.
Additionally, inspectors examined the fractured nose wheel pivot. They discovered that the component in use differed from the original design drawings. A subsequent stress analysis revealed that this specific part possessed only 23% of the required bending strength compared to the original design. There was no documentation available to the owner or the PFA regarding this modification.
Findings
- The aircraft's recorded empty weight was inaccurate, leading to a potential exceedance of the maximum all-up weight.
- An undocumented modification to the nose gear resulted in a component with significantly reduced structural strength.
- The failure of the nose wheel pivot was linked to the use of a part that was not as strong as the original design.