Two Instances Of Engine Fires Prompted The Move

The FAA posted a proposed AD in the Federal Register Thursday for all General Electric Company (GE) CF34-8C and CF34-8E turbofan engines with certain part numbers (P/N) of operability bleed valves (OBV) installed. This proposed AD was prompted by three failure events of ring lock fuel  fittings on the OBV. Two of those events led to an engine fire. This  proposed AD would require the affected OBVs be removed from service and  replaced with OBVs eligible for installation. The FAA is proposing this AD  to prevent failure of OBV ring lock fuel fittings, engine fuel leakage, uncontrolled fire, and damage to the airplane.

The agency received reports of three failure events of OBV ring lock fuel fittings on GE CF34-8C turbofan engines. Two of those events led to an engine fire. Investigation revealed that the ring lock fittings failed due to fatigue caused by improper broaching of the OBV housing during manufacture, and, improper installation of the ring lock fittings during OBV assembly. GE CF34-8E turbofan engines also use the affected OBVs and would be affected by this proposed AD.

The FAA says that this condition, if not corrected, could result in failure of OBV ring lock fuel fittings, engine fuel leakage, uncontrolled fire, and damage to the airplane.

The repairs are expected to affect some 300 engines installed on Embraer and Bombardier airplanes of U.S. registry. The FAA estimates that it would take about two hours per engine to perform the actions required by this proposed AD, and that the average labor rate is $85 per hour. Required parts would cost about $25,000 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $7,551,000.

Comments on the proposed AD are due to the FAA by February 11, 2013.

FMI: Proposed AD