What happened
On 27 October 2012, a Jodel D150 Mascaret, registration G-BHEG, was performing a private flight departing from Dunkeswell Airfield. During the climb out, at an altitude of roughly 400 feet, the pilot heard an audible thud and observed the landing light cover on the left wing leading edge splitting. The failure caused the upper half of the cover to deflect upwards and the lower half to deflect downwards.
This structural failure altered the airflow, creating a gap beneath the front spar that allowed air to enter the wing structure, causing the fabric covering to bulge. The pilot experienced significant control difficulties, specifically a persistent yaw and roll to the left. Despite attempting to level the wings and managing the aircraft at approximately 50 feet, the pilot found that applying power caused extreme instability. After declaring a MAYDAY, the pilot attempted to navigate toward Runway 15, but the aircraft continued to turn left toward taxiing traffic. In an effort to clear ground vehicles, the pilot manipulated the nose position, which induced further yaw. Ultimately, the left wing struck the ground, causing the aircraft to slew across the grass at the end of Runway 17.
The investigation
The investigation focused on the failure of the landing light cover. It was determined that the component had been constructed from polycarbonate material that had been bent around the leading edge profile. This-non-moulded approach introduced residual stresses into the material, which likely caused the cracking and subsequent failure. The investigation noted that the correct part should consist of Perspex moulded specifically to the shape of the leading edge. The investigation also consulted the French BEA, which indicated no prior known accidents resulting from this specific type of component failure.