What happened
On 5 October 2013, an Ikarus C42 FB UK, registration G-ILRS, was performing a private flight from East Fortune Airfield in East Lothian. During the takeoff roll, approximately 50 feet after the start of the run, the right wing began to rotate upwards relative to the fuselage. The pilot reacted immediately by abandoning the takeoff attempt.
There were no injuries to the pilot or the single passenger on board. However, the aircraft sustained damage to both the left and right wings, as well as the right flap.
The investigation
The investigation focused on the wing-fold mechanism of the aircraft, which allows the wings to be stowed parallel to the fuselage. On the day of the incident, the pilot had removed the aircraft from its trailer and unfolded the wings with help from another pilot. The pilot followed a procedure outlined in the C42 Owners Manual, which involved having an assistant hold the wingtip while the pilot secured the lower end of the wing strut to the fuselage. To verify the connection, the pilot would lift the wingtip to ensure the strut was correctly attached.
The investigation established that the wing strut lower attachment bolt had not been properly installed. Specifically, the bolt had passed through the fuselage mounting bracket but had failed to pass through the strut itself.
Findings
- The primary cause of the wing rotation was the incorrect fitting of the wing strut lower attachment bolt.
- The pilot had relied on the assistance of another pilot to perform the wing-folding process.
- The pilot did not personally repeat the final check of the attachment because he believed the assistant had already verified the connection by lifting the wingtip.