19981104031359A

Acft stalled and crashed upon takeoff. (.19)on November 4, 1998, at 1045 hours pacific standard time, a Piper PA-46, N50JG, crashed during takeoff from runway 09 at the Mammoth, California, airport. The aircraft was substantially damaged and two of the four occupants received serious injuries. The other two occupants received minor injuires. Visual meteorological conditions existed at the time of the 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 aircarft 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." Examination of the elevator trim tab and the elevator trim position indicator in the cockpit revealed a full nose up trim. (.4) 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 WI nds 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. (-23) 11/04/98, 10:45 am, Mammoth Lakes airport, Mammoth, CA. During the takeoff run at about 65 mph (normal rotation speed is about 80-85 mph), the pilot reported that the auto pilot trimmed the elevator trim to the full nose up position. The aircraft started to climb and felt mushy. The left wing dropped, he pulled the landing gear up and while trying to level the aircraft, it impacted into the ground between the runway and taxiway and slid about 200 feet onto the taxiway, pointing about 220 degrees. The pilot immediately evacuated everyone off of the aircraft. (3 passengers and 2 dogs). No fire ensued. All occupants were transported to the L0CAL hospital for check ups. The pilot sustained back injuries.