MAMMOTH, CA, USA
N50JG
Piper PA-46-350P
Witnesses said the aircraft took off prematurely and over rotated to a nose high attitude. Shortly thereafter, the aircraft hit the ground tail first then the nose. The aircraft veered off the side runway and came to rest on a taxiway. The winds were reported as calm at the time. The pilot told the witness that he stalled on takeoff. Immediately after the accident, the position of the elevator trim tab and the cockpit elevator trim indicator were found in the full nose up trim positions. The pilot reported that the aircraft had a dead battery and required external power for the start. During this process, the autopilot cycled twice. The pilot stated that he performed a normal run-up and trimmed the aircraft for takeoff. He said that at 62 knots the autopilot ran the pitch trim to the full nose up position and the aircraft pitched prematurely to a nose high attitude and lifted off the ground. The pilot then retracted the landing gear. The left wing dropped and the airplane settled back to the ground. According to the auto pilot manufacturer, the pitch servo capstans are designed with a clutch that will slip at 25 pounds of control wheel force. According to flight test data supplied by Piper, the control wheel force required to hold 62-knot speed at full trim tab deflection would be less than 40 pounds.
On November 4, 1998, at 1045 hours Pacific standard time, a Piper PA-46-350P, N50JG, crashed during takeoff from runway 09 at the Mammoth, California, airport. The aircraft, owned and operated by the pilot under 14 CFR Part 91, was substantially damaged. The private pilot and one passenger received serious injuries. The other two passengers received minor injuries. Visual meteorological conditions existed at the time and no flight plan was filed for the personal VFR flight to Las Vegas, Nevada. According to the airport manager, the aircraft took off prematurely and over rotated to a nose high attitude. Shortly thereafter, the aircraft hit the ground tail first then the nose. The aircraft veered off the side of the 7,000-foot-long runway and came to rest on a taxiway. The winds were reported as calm at the time. The pilot told the manager that he "stalled on takeoff." At the request of the Safety Board, the airport manager documented the position of the elevator trim tab and the cockpit elevator trim indicator in the full nose up trim positions. In his written report to the Safety Board, the pilot said that the aircraft had a dead battery and required external power for the start. During this process, the autopilot "cycled twice." The pilot stated that he performed a normal run-up and trimmed the aircraft for takeoff. At 62 knots, the aircraft pitched prematurely to a nose high attitude and lifted off the ground. The pilot retracted the landing gear and the airplane settled back to the ground. The pilot told Federal Aviation Administration inspectors from the Reno, Nevada, Flight Standards District Office that the autopilot ran the pitch trim to the full nose up position just prior to rotation speed. The aircraft lifted off and immediately "felt mushy." The pilot said the left wing dropped and the airplane settled back onto the runway. According to the autopilot manufacturer, the autopilot pitch servo capstans are designed with a clutch that will slip at 25 pounds of control wheel force. Flight test data was supplied by Piper Aircraft concerning control wheel force versus pitch trim tab position. The two speeds for which data points were supplied were 110 KCAS and 200 KCAS. The control wheel force required to hold speed at full trim tab deflection was 48 and 71 pounds, respectively.
The pilot's failure to ensure that the autopilot was off prior to takeoff, and, his failure to maintain pitch control during the resultant pitch trim excursion during the takeoff ground roll.
Source: NTSB Aviation Accident Database
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