Gulfstream-Schweizer A/C Corp G-164B N425LS accident near Bonifay, Florida

Probable cause

A partial blockage of the No. 2 bearing oil nozzle jet by bearing material, which resulted in oil starvation and the subsequent failure of the No. 2 bearing and total loss of engine power.

NTSB analysis

The commercial pilot was conducting a cross-country positioning flight in the turboprop airplane. The pilot reported that, while on approach to the destination airport, the propeller began wind-milling, and "pieces of metal" began coming out of the right engine exhaust duct. The pilot subsequently conducted a forced landing, during which the airplane struck trees.

Postaccident examination of the engine revealed that the No. 2 bearing oil nozzle jet was partially blocked, which resulted in oil starvation and the subsequent disintegration of the No. 2 roller bearing. The material blocking the oil nozzle jet was consistent with material used in the composition of the bearing races and rollers.

A review of maintenance records revealed that the No. 1 engine bearing had failed about 1,000 flight hours before the accident and was replaced along with the No. 2 bearing. In addition, the Nos. 1 through 5 bearings were replaced about 300 flight hours before the accident. The investigation could not determine if the No. 2 bearing oil nozzle jet was blocked by bearing material as a result of the previous bearing failure or if the blockage developed during the engine's subsequent operation.

Text from the NTSB. Open the NTSB docket for ERA14LA368 for the full record.