NTSB Identification: IAD99FA004B
Accident occurred Monday, October 05, 1998 in WARREN, VT
Probable Cause Approval Date: 06/22/2000
Aircraft: Burkhart Grob G 103C, registration: N103VT
Injuries: 1 Fatal,1 Serious,1 Minor.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
During takeoff for a glider tow operation, the towplane and the glider both became airborne. An FAA Inspector witnessed the takeoff and said his attention was drawn to the 'erratic pitch changes' of the glider. The glider pilot's canopy was open, and the pilot repeatedly attempted to close the canopy. Pitch changes and climbs above the tow plane accompanied each attempt to close the canopy. As the towrope reached a vertical position, the towplane struck the ground, nosed over, and came to rest inverted. The towrope separated, and the glider continued past the towplane, rolled left to an inverted position and impacted the ground. The towrope in use at the time of the accident employed a 'Sweitzer Ring' to attach at the tow plane and a 'Tost Ring' to attach at the glider. Both rings were attached to their respective airplanes and both release mechanisms were operational. According to the 1998 Soaring Flight Manual sponsored by the Soaring Society of America: 'When the sailplane is too high, it can pull the tail of the towplane up, making it difficult, if not impossible, for the towplane to take off... If corrective action is not taken, the only alternative for the tow pilot is to release the towline...If for any reason, the sailplane pilot loses sight of the towplane, he should release immediately.'
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The glider pilot's failure to perform the emergency tow release and abort the takeoff. A factor in the accident was the glider pilot's improper decision to make repeated attempts to close the canopy in flight. Full narrative available
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