What happened
During the initial climb phase following takeoff, the flight crew observed an anomaly in the performance of the number two engine. As the aircraft ascended through approximately 3,000 feet, the Engine Pressure Ratio (EPR) for that engine dropped by about 0.08, falling from a reading of roughly 1.82 to 1.74. Shortly thereafter, the first officer reported that the Exhaust Gas Temperature (EGT) or associated vibration indicator on the number two engine had reached its maximum indication.
At an altitude of approximately 4,000 feet, a loud, explosive noise emanated from the rear section of the aircraft as the right engine lost power completely. The crew successfully secured the failed engine and initiated a return to Tampa International Airport. The aircraft landed safely without any further complications or incidents.
The investigation
Post-accident examination of the number two engine revealed significant internal damage. Turbine blades were found to have exited through the side of the engine tailpipe, indicating a violent internal failure. A detailed teardown of the engine components uncovered critical defects in the high-pressure compressor assembly.
Specifically, the high-pressure compressor center tube sealing ring was missing an approximate 1-inch circumferential piece of hard surface plating from its outside diameter sealing surface. This defect was located in axial alignment with a gap found in the rear piston ring. Investigation confirmed that neither ring conformed to the manufacturer's design specifications.
Further analysis indicated that hot air had caused coking of the engine oil. The turbine shaft had failed approximately 13 inches forward of the 4-1/2 bearing. Examination of the 4-1/2 bearing seals showed they were damaged, with seven seals displaying coke deposits. Additionally, the low-pressure turbine assembly had moved aft, resulting in intermeshing damage to the blades and stators.