Cessna 560XL N547CS incident near Abbeville, Louisiana

Probable cause

The pitch trim control cable failed due to fatigue, rendering the elevator trim inoperative.

NTSB analysis

During the initial climb and approaching the assigned altitude, the captain noticed an abnormal feel in the flight controls followed by the pitch trim annunciator light coming on. The captain disconnected the autopilot and felt the airplane’s nose immediately pitch up. The captain immediately corrected for the abnormal pressure and attempted to reduce the control forces via the electric and manual trim to no avail. The captain slowed the airplane to the speed at which it was trimmed and ran the checklist for a jammed elevator trim. The captain notified his company dispatch, declared an emergency with approach control, and landed the airplane uneventfully. A postincident examination showed that the elevator trim cable had failed due to fatigue. A laboratory examination showed slight wear on the individual cable strands. The cable had been installed at the time of manufacture and had accumulated 5,445.3 total hours. Following the examination, the airplane manufacturer determined that the cable required replacement with one made of improved rope wire material and issued a service bulletin requiring owners and operators to replace the elevator trim cable with the new cable within 300 hours or 6 months from receipt of the service bulletin.

Text from the NTSB. Open the NTSB docket for CEN11IA286 for the full record.