Event Description
A scheduled transcontinental flight from New York to Los Angeles experienced an in-flight engine failure while at cruise. The #1 engine failed after several stage 1 high pressure turbine rotor blades separated without warning from their platforms. The blade separations led to the disintegration of the high pressure turbine assembly and subsequent engine failure.
Investigation Findings
Examination determined that the initial blade separation originated at a forward cooling hole on one of the blades. The separation was found to be fatigue-induced. The fatigue was most likely caused by a degradation of the cooling airflow pattern within the blade, which was induced by an airflow leak not associated with the blade cooling holes.
Engine Failure
The multiple blade separations resulted in the complete disintegration of the high pressure turbine assembly, causing the #1 engine to fail. The aircraft continued as able, but no further details about the flight's outcome or any potential operational consequences were provided in the investigation report.