NTSB Identification: LAX01FA144.
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Accident occurred Saturday, April 14, 2001 in Williams, CA
Probable Cause Approval Date: 01/23/2002
Aircraft: Schleicher ASW-20, registration: N47TR
Injuries: 1 Fatal.
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 the takeoff, the glider began an uncontrolled climb at a 45-degree nose up attitude behind the tow plane. The tow plane pilot was forced to cut the tow rope due to the severe pitch down moment caused by the glider. The glider then arced over into a 45-degree nose down dive and hit the ground. The glider's flight control system was equipped with Hotalier quick disconnect fittings at various locations to facilitate the disassembly of the glider for trailer transport. A postaccident examination of the flight control system disclosed that the elevator control push rod was disconnected from the elevator at a quick disconnect fitting in the vertical stabilizer. There was no damage noted to the elevator bell crank or the terminal end of the elevator control push rod. A close friend and former partner in the glider was interviewed. He was present on the day of the accident and knew the pilot very well. He stated that he and the pilot had purchased the glider a little less than a year prior to the accident. The pilot had flown it over 50 times and had assembled it as many as 25 times. On the day of the accident, he and the pilot completed a control check while qued for the tow plane. He stated that he held the elevator while the pilot applied full up elevator control input. He felt the elevator move in the up position. He said neither the pilot nor he attempted to apply full nose down control input, as it was assumed the elevator was properly attached to the control rod fitting. He stated that in retrospect, the only way to positively check the connection is to hold the elevator in the up position while the pilot applies full nose down control input.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The failure of the pilot to attach the elevator control rod to the elevator, resulting in a loss of pitch control and subsequent ground impact. Additional factors were the failure to complete a positive control check and the lack of clear guidance in the assembly procedures. Full narrative available
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