DG-505 rear headrest jams elevator control on final

The pilot of a DG-505 was seriously injured when the rear-cockpit headrest jammed the aft control column on final, locking out up-elevator and forcing a steep dive into the ground; destroyed. The pilot was experienced and on solo conversion training. The headrest restraint — a non-conforming electrical wire substituting the manufacturer's nylon/perlon cords — failed at its rear harness point. The headrest dropped behind the aft column and blocked rearward travel. The glider pitched steeply nose-down, struck nose-first, bounced with tailplane loss and hit again. A Technical Note for daily headrest-cord inspection was not in the Flight Manual.

1. Final approach, normal height/speed: After an uneventful winch launch and circuit, the glider turned onto final at appropriate height and speed; the pilot, on solo conversion training, was under duty-instructor supervision.
2. Non-conforming headrest restraint cable: The manufacturer's nylon/perlon headrest cords had been replaced with a non-conforming electrical cable of different properties, accepted at the club and not flagged in inspections.
3. Inspection regime gap: A Technical Note requiring daily inspection of the rear headrest ropes had not been incorporated into the cockpit Flight Manual copy and was not acted on during annual and daily checks.
4. Headrest restraint cable fails on final: During final approach, the non-conforming electrical cable restraining the hinged rear-cockpit headrest failed at its attachment to the rear shoulder-harness point, freeing the headrest.
5. Headrest jams aft control column: The headrest pivoted forward onto the rear control column and then dropped behind it, blocking rearward stick travel and restricting up-elevator deflection.
6. Unrecoverable steep nose-down dive: With aft stick blocked, the glider adopted a steep nose-down attitude and descended rapidly into the airfield with little change in attitude.
7. Nose-first impact, tail bounce: The glider struck the ground nose-first, bounced with tail impact and tailplane separation, then impacted again; pilot seriously injured, airframe destroyed.