What happened
On December 2, 2013, an ELA 07 gyroplane, registration 34-AHF, was performing circuit training at the Coulomermiers - Voisins aerodrome. The flight was an instructional session involving an instructor and a student, both of whom were nearing the completion of their gyroplane qualification.
During the final turn of the circuit, the aircraft experienced a loss of control and struck the ground. A witness near the airfield observed the aircraft following a nearly vertical descent path, noting that the aircraft caught fire immediately upon impact. The wreckage was located approximately 410 meters from the threshold of runway 09, near the paved extension of the strip. The impact resulted in two fatalities, as both the instructor and the student died in the accident, and the aircraft was destroyed.
The investigation
The BEA examined the wreckage and the flight instruments to determine the cause of the accident. Investigators found that the aircraft was structurally intact at the moment of impact and that the flight controls remained connected to the control surfaces. The engine was running at a power setting below full power, and the main rotor was in rotation. However, the aircraft was tilted significantly to the left, with the rotor disk at an angle greater than 90 degrees relative to the horizon.
Instrument readings at the time of impact revealed a critical discrepancy: the airspeed indicator in the front seat showed 170 km/h, which exceeded the manufacturer's maximum speed (VNE) of 160 km/h, while the rear seat indicator showed only 100 km/h. The investigation also noted that the rear airspeed indicator had been known to fluctuate inconsistently during previous flights.
Findings
- The primary cause of the accident was a loss of control during the final turn.
- The investigation identified a high probability that the airspeed indication in the instructor's seat was erroneous, which likely prevented the timely detection of a dangerous flight condition.
- The aircraft had entered a prohibited height/speed envelope, where the combination of low altitude and insufficient airspeed left no margin to recover the flight path for landing.
- While the instructor was highly experienced in commercial aviation, he had very limited experience specifically operating this particular gyroplane, as it was the student's privately owned aircraft.