What happened
On 25 June 2019, a SCHEMPP HIRTH - JANUS C glider, registration F-CFAL, was performing a winch launch at Laval Entrammes aerodrome in France. During the initial climb, the pilot in the front seat requested the winch operator to increase speed on two separate occasions. Following release at an altitude of approximately 430 m, the aircraft began to lose altitude.
As the glider descended to 300 m, the pilots decided to abort the cross-country flight and return to the unpaved runway 32. The pilot in the rear seat assumed control of the aircraft. While on the left-hand downwind leg at an altitude of approximately 30 m, the pilot realized the aircraft was too low to reach the runway threshold. In an attempt to reach the midpoint of the runway, the pilot executed a left turn, during which the glider struck the ground in the obstacle-free zone at a 30-degree angle to the centerline. The aircraft came to rest 65 m further along the edge of the paved runway. Both pilots evacuated the aircraft without injury, though the glider was substantially damaged.
The investigation
The BEA examined the aircraft's flight data, radio communications, and statements from the crew and ground personnel. The investigation focused on why the air brakes deployed during the climb and why the pilots failed to correct the glide path.
Investigators found that the air brake control, located on the left side of the cockpit, had been left in an unlocked position. During pre-take-off checks, the pilot perceived resistance in the control and believed the brakes were locked. The rear seat pilot also failed to verify the position of the brakes, as his attention was focused on managing the approach.
Additionally, a person on the ground observed the orange air brakes extending and attempted to warn the pilots via the winch truck's radio. However, this message was not heard by the crew, likely due to improper use of the radio microphone by the observer. The investigation also noted that the air brake control mechanism can be difficult to fully lock, a factor present in similar previous occurrences.