Miami International Airport
Aircraft Accident/Incident Report

Miami, Florida 33159
Wednesday, October 7, 1998 7:09 EDT

During the initial part of the takeoff, prior to the engines reaching takeoff power, the No. 2 engine had an uncontained failure of the 8th stage HPC disk. The takeoff was aborted, the passengers were bussed to the terminal, and the aircraft was towed to the gate. Metallurgical examination of the 8th stage HPC disk showed that a significant amount of cadmium was present on steel base metal in the area of the fracture surfaces and the surface had an inadequate nickel coating. The disk had accumulated 359 flight hours since overhaul. The disk had been nickel-cadmium plated in March 1996 and was stored until February 1998, when it was installed in the accident engine during repair. Other HPC disk installed in the accident engine, which had been nickel-cadmium plated by the same company as the 8th stage HPC disk, were also found to have inadequate nickel coating. During nickel-cadmium plating the nickel acts as a barrier coating between the cadmium and the steel part to prevent cadmium from contacting the steel part, which can cause cadmium embrittlement.

The catastrophic failure of the 8th stage high pressure compressor disk from cadmium embrittlement as a result of improper adherence to the prescribed plating procedures and requirements by the company that last plated the disk. Contributing to the accident was the failure of the engine repair company to provide adequate surveillance and oversight of the plating company, the engine repair companies use of an unauthorized repair vendor, the plating company, and the engine repair companies failure to inform the aircraft operator that they had used the plating company which was not on the aircraft operators vendor list. Also contributing to the accident was the aircraft operators failure to audit the engine repair company to the level of detail that they would have discovered the engine repair company was using an unauthorized repair vendor.