Piper PA-34-220T N104NW accident near Ankeny, Iowa

Probable cause

The failure of the stabilator control cable due to wear. Contributing to the accident was the inadequate maintenance inspection of the stabilator control cable.

NTSB analysis

The pilot reported that when he pulled back on the control yoke during the landing flare the nose of the airplane did not pitch up. The airplane landed hard on the nosewheel and bounced several times before stopping on the runway. A postaccident examination of the airplane revealed that the stabilator control cable had fractured in two pieces. The location of the fracture was in the unobstructed area in the tail cone; the location of the fracture was not associated with a pulley, fairlead, or bulkhead, and no rubbing or chaffing was found in the area of the fracture. The entire length of the cable was covered with dried black grease and the majority of the fractured ends of the individual wires exhibited wear damage with the exposed surfaces of the wires covered in grease. The ends of the fractured wires exhibited features typical of overstress separation, with no evidence of fatigue cracking. Federal Aviation Administration guidance states that the inspection and repair of control cables should be accomplished during annual inspections. The aircraft maintenance logbooks indicated that the last annual maintenance inspection was conducted about three months prior to the accident, equating to 17 flight hours. The logbook entry for that inspection indicated that the control cables were checked for correct rigging and cable tensions. The logbook entry stated, “Stabilator OK.” There was no indication of any repair or replacement of the stabilator control cable.

Text from the NTSB. Open the NTSB docket for CEN10LA312 for the full record.