Update: The cost information below should read "$520,760 to U.S. operators."
The FAA announced today that it has adopted a new airworthiness directive (AD) for GE CF34-10E turbofan engines. The AD seeks to remedy reported heavy wear found on the seating surface of the center vent duct support ring, and also on the inside diameter of the fan drive shaft at the mating location. Read the full text of the document here at the U.S. Government Printing Office web site.
If untreated, this wear on the center vent duct support ring and/or the inside diameter of the fan drive shaft could cause a fan drive shaft failure, which could result in an uncontained engine failure and damage to the aircraft. This AD will affect 71 engines installed in aircraft that are registered in the United States.
This AD goes into effect on Feb 27, 2012 and requires CF34-10E operators to inspect the center vent duct support ring and fan drive shaft for wear. The discovery of wear on either item would require removing all center vent duct support assemblies and/or any fan drive shaft on the engine. The specific inspection criteria for the center vent duct assembly and the fan drive shaft and removal requirements are outlined in section (f) of the document.
Operators must comply with this AD on each CF34-10E engine before it accumulates 11,500 total in-service cycles. The FAA estimates that compliance with the AD will be about $520,760 to U.S. operators (not per engine, as previously stated), which includes labor and material costs. The administration estimates that a replacement center vent duct support assembly costs $3,080, and estimates that two fan drive shafts at the price of $126,900 each will also need to be replaced if wear is found. It takes about eight work hours per engine to reform visual inspections and a replacement of the center vent duct support assembly, and the average labor rate is a about $85 per work hour.