What happened
On March 18, 2005, at approximately 15:45, a Quicky 503 ultralight, identified as 81-TA, was conducting a training flight at the Lavaur airfield. Following a series of low-altitude flyovers and interrupted approaches on runway 30, the crew cleared the runway and returned to the threshold for takeoff.
During the initial climb, the student pilot was caught off guard by the aircraft's reaction to a lateral wind gust. The instructor, seated in the rear position, attempted to regain control by manipulating the control bar cables. Despite these efforts, the aircraft veered off course and struck a poplar tree located 27 meters to the right of the runway centerline. The aircraft continued in level flight for approximately 40 meters before striking a grove of trees and crashing to the ground. The impact with the first tree occurred at an altitude of six meters. The accident resulted in one fatality (the instructor) and one injury (the student), and the aircraft was destroyed.
The investigation
The investigation focused on the aircraft's performance, the environmental conditions, and the airfield's obstacle clearance zones. Investigators examined the engine and the wreckage, finding no evidence of mechanical malfunction. Meteorological conditions at the time were reported as CAVOK with temperatures of 25°C and winds from 110° at 6 to 11 knots.
Regarding the airfield layout, the investigation noted that at the time of the accident, the recommended obstacle clearance surface for the platform required obstacles not to penetrate a 40% slope. The impact point on the first tree was found to be on a surface with an 80% slope. It was also noted that current regulations for ultralight platforms have since reduced this required slope to 30%.
Findings
- The pilot underestimated the effects of a tailwind on the aircraft's climb performance.
- There was insufficient maintenance of the aircraft platform.
- The aircraft encountered significant turbulence during the takeoff phase.