Primary finding
Probable cause
The inadvertent deployment of the spoilers during the aero tow takeoff for undetermined reasons, resulting in a hard landing.
Investigator assessment
Analysis narrative
The 630-hour glider commercial pilot reported that prior to departure from the 4,200-feet by 400-feet wide grass-turf gliderport, he followed his checklist items which included; checking and closing the spoilers, checking the seat belts and shoulder harnesses. During the aero tow takeoff, the pilot noticed the uncommanded opening of the spoilers and he elected to release from the aero tow. During the landing on the grass runway, the glider touched down hard. The glider received minor damage to its landing gear and the pilot was seriously injured. The reason for the uncommanded extension of the spoilers could not be determined.
Source record
Factual narrative
The 630-hour glider commercial pilot reported that prior to departure from the 4,200-feet by 400-feet wide grass-turf gliderport, he followed his checklist items which included; checking and closing the spoilers, checking the seat belts and shoulder harnesses. During the aero tow takeoff, the pilot noticed the uncommanded opening of the spoilers and he elected to released from the aero tow. During the landing on the grass runway, the glider touched down hard. The glider received minor damage to its landing gear and the pilot was seriously injured. The reason for the uncommanded extension of the spoilers could not be determined.