What happened
On June 22, 2002, a Grob G 103 Twin Astir II glider, registration F-CFYO, was performing a towed takeoff from the Tarbes Laloubère airfield. Approximately two to three minutes into the flight, while at an altitude of roughly 150 meters, the glider entered a right-hand turn. During this maneuver, the rear section of the canopy opened unexpectedly.
In response to the sudden opening, the pilot reflexively released the tow cable. Simultaneously, the tow plane pilot transmitted a radio message instructing the glider pilot not to release the cable. Attempting to manage the emergency, the pilot performed a 180-degree turn and established a left-hand base leg pattern in an attempt to land on runway 26. The pilot notified air traffic via radio that the altitude was insufficient to reach the airfield and indicated an intention to land within the nearby industrial zone.
However, the aerodynamic drag caused by the open canopy made the aircraft difficult to control. At an altitude of approximately 20 meters, the glider entered an asymmetric stall. The aircraft struck the ground, with the right wing hitting first, followed by the left wing impacting a highway safety barrier. The impact resulted in the destruction of the aircraft and one injury to the pilot.
The investigation
Investigators examined the canopy mechanism, which consists of two mobile parts pivoting around an axis on the right side of the cockpit. The locking system relies on two independent latches located on the left side of the cockpit.
During the inquiry, the pilot stated they were uncertain whether they had verified the rear canopy's locking status prior to takeoff. Additionally, the pilot noted that during the tow, their hand had been positioned on the cable release handle, which may have influenced their immediate reaction to the canopy failure.