Airworthiness Directives; General Electric Company (GE) CF6-80C2B Series Turbofan Engines

The FAA is adopting a new airworthiness directive (AD) for GE CF6-80C2B series turbofan engines with electronic control units (ECUs), installed on Boeing 747 and 767 series airplanes. This AD requires installing software version 8.2.Q1 to the engine ECU, which increases the engine's 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. Though the root cause investigation is not yet complete, we believe exposure to ice crystals during flight is associated with these flameout events. We are issuing this AD to provide increased margin to flameout, which will minimize the potential of an all-engine flameout event caused by ice accretion and shedding during flight.