Piper PA-34-200T N633TC incident near Tallahassee, Florida

Probable cause

The failure of the elevator trim cable due to fatigue cracking, which resulted from maintenance personnel’s repeated inadequate inspection of the cable.

NTSB analysis

According to the flight instructor, during the initial climb, the student pilot noticed a problem with the elevator trim wheel. The flight instructor moved the trim wheel and noted no resistance. He then looked down at the wheel and observed the trim cable protruding from its side. The flight instructor assumed control of the airplane, advised the tower air traffic controller of the emergency, and landed the airplane without incident.

Examination of the elevator trim cable assembly revealed that the trim cable failed due to fatigue cracking of the individual wires. The wire breaks were so numerous and over such a sizable length that they should have been detectable by a visual inspection. However, a review of the aircraft logbooks revealed that maintenance personnel did not detect the fatigue cracking of the wires during the most recent 100-hour and annual inspections nor during compliance with an airworthiness directive (AD) that required, in part, that all control cables be inspected for broken wires strands and that any broken wire strands be replaced; the inspections and AD were accomplished less than 2 months before the incident.

Text from the NTSB. Open the NTSB docket for ERA13IA267 for the full record.