Piper PA28 N40831 accident near Sarasota, Florida

Probable cause

A partial loss of engine power due to a failed throttle cable.

NTSB analysis

The student pilot was turning from downwind to base in the traffic pattern, with 10° flap extension, when he noticed that the throttle lever was stuck with the engine operating at 2,000 rpm. He turned onto final approach with 25° flap extension and realized that the descent rate was too great and that the airplane was not going to make it to the runway. He retracted the flaps to 0° to reduce drag, turned right to avoid houses at the approach end of the runway, and landed the airplane in an adjacent bay.

Metallurgical examination of the throttle cable revealed a worn Teflon liner. When intact, the liner supported the inner cable and prevented metal-to-metal contact with the helical coil of the cable housing. Six of the seven wires of the inner cable had separated due to metal-to-metal contact wear. The seventh (single central) wire did not have the capacity to resist compressive and torsional loading of the cable, which led to collapse and torsional unfurling of the cable.

The airplane was manufactured 48 years before the accident and had accrued about 14,000 hours of operation. There were no life-limited components on the make and model airplane and no requirement to replace the throttle cable at a scheduled interval. Review of maintenance records dating back 2 years before the accident did not reveal any problems with the throttle.

Text from the NTSB. Open the NTSB docket for ERA22LA054 for the full record.