Incident Summary
On July 1, 2013, at EPBA aerodrome, an SZD-9 bis 1E glider experienced an in-flight opening and detachment of the rear canopy during a winch launch. The incident occurred after takeoff at an altitude of approximately 50 meters. The canopy glazing shattered upon impact with the ground, but the glider itself sustained no damage. The pilot released the towline and performed a landing circuit, after which the glider landed without further incident.
Findings
The instructor reported that the canopy was properly closed and locked before the launch. An inspection of the rear canopy lock mechanism revealed that the spring pressure on the lock knob was significantly weaker compared to the other two Bocian gliders in use. During the takeoff roll, the student made an abrupt control stick movement, causing the glider to make hard contact with the ground first on the front skid and then on the tail skid. This hard landing, combined with the inertia of the weakly sprung lock knob, likely caused the lock to become unlatched.
Preventive Measures
Following the incident, the operator (Aeroklub Bielsko-Bialski) inspected the spring pressure on the lock mechanisms of the other Bocian gliders in the fleet. The event was discussed with the instructors involved in training, with particular emphasis on the proper method of checking the closure and locking of the rear canopy on the Bocian glider.
No safety recommendations were issued by the investigating commission.