AD FAA-2005-21238

The FAA is superseding an existing airworthiness directive (AD) for General Electric (GE) CF6-80E1 series turbofan engines. That AD currently requires removing electronic control unit (ECU) software version E.1.M. or earlier installed software, and installing improved software for the ECU. This AD requires removing software version E.1.N or earlier from the engine ECU. Engines with the new version software will have increased margin to flameout. This AD results from reports of engine flameout events during flight, including reports of events where all engines simultaneously experienced a flameout or other adverse operation. Although the root cause investigation is not yet complete, we believe that exposure to ice crystals during flight is associated with these flameout events. We are issuing this AD to minimize the potential of an all-engine flameout event caused by ice accretion and shedding during flight.