Incident Description
While operating at recommended power settings during cruise, the left engine's oil pressure and torque indications began to fluctuate and drop. In response, the power lever was retarded. A popping sound was subsequently heard, prompting the crew to shut down the engine. A precautionary landing was then performed in Atlanta.
Engine Examination
Following the incident, the engine was disassembled for inspection. The examination disclosed a failure of the No. 1 bearing. Additionally, blade tip feathering was observed on the first and second stage compressor blades, as well as on the impeller stage. The oil nozzle was found to be unobstructed.
Bearing Details
The failed bearing had accumulated 113 hours in service at the time of the incident. Pratt and Whitney had obtained a new vendor for this bearing component.