NTSB Identification: CEN10LA052
14 CFR Part 91: General Aviation
Accident occurred Tuesday, November 17, 2009 in Saginaw, TX
Probable Cause Approval Date: 08/12/2010
Aircraft: PIPER PA-34-200T, registration: N8297P
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot said that he took off and did not engage the autopilot, but did use the electric trim switch on the control yoke to establish a climb attitude after takeoff. When he activated the trim switch, the airplane "pitched down rapidly." Despite his application of full up elevator to arrest the descent, the airplane continued to descend. The pilot was forced to make a landing in an open field. During the ensuing forced landing, the airplane sustained substantial damage to both wings and fuselage. The pitch trim drum inner shaft was found to be in the full-nose-down position. Examination of the cockpit revealed all circuit breakers were closed and the master switch had been secured. The flight computer, trim servo, directional gyro, flight command indicator, pictorial navigation indicator, and control yoke were functionally tested and no defects were noted. The original control yoke trim switch had been replaced. The switch wiring was not the original wiring and did not correspond to the original color codes on the wires. The wire colors were written on pieces of masking tape which were wrapped around each corresponding wire. One of the wires was pinched and pressing on the switch wafer stack; according to a representative of the manufacturer the pinched wire pressing on the switch wafer stack could have resulted in a runaway trim condition.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's inability to maintain control of the airplane due to a pinched trim system wire that resulted in a runaway nose-down pitch trim.

Full narrative available

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