What happened
On 13 March 2017, a Savannah VG Jabiru, registration G-WHYS, was conducting a private flight from Swanwick, Derbyshire, to Swansea Airport. Approximately 90 minutes into the journey, as the aircraft approached Abergavenny, the pilot encountered significant cloud cover and intense turbulence. The turbulence was severe enough to lift the pilot from his seat, causing him to strike his head against the cabin roof. In response to the deteriorating weather, the pilot slowed the aircraft, adjusted his course to the south, and eventually returned to his home airfield to terminate the flight.
Two days after the flight, while moving the aircraft out of its hangar, the pilot noticed that the right rear lift strut attachment bracket had been bent forward. This discovery led to an investigation to determine if the turbulence encountered during the flight had caused the structural distortion.
The investigation
Investigators examined the aircraft's right wing upper skin, which was removed to inspect the area beneath the attachment point. This revealed cracks in the wing rib adjacent to the lift strut attachment. Notably, the cracks were surrounded by accumulated dirt and debris, which suggested that the distortion was not a recent occurrence.
Further technical analysis was performed by the British Microlight Aircraft Association (BMAA). Calculations regarding the gust loads experienced during the flight indicated that the forces encountered were below the aircraft's structural limit loads. Additionally, the manufacturer reviewed the relevant approval documentation and concluded that the damage was likely the result of adverse loading while the aircraft was on the ground.
Findings
- The investigation established that the damage to the lift strut attachment and wing rib was pre-existing and unrelated to the flight on 13 March 2017.
- The presence of dirt and debris within the distorted area indicated the damage had existed for some time.
- The specific cause of the ground-based loading that resulted in the damage was not determined.