FAA Issues AD for CF34 Turbofans

The FAA has issued a proposed Airworthiness Directive for GE CF34 turbofan engines with high-pressure-rotor, four-step, air-balance-piston, stationary seals to remove these seals and incorporate an eight-step seal at the next piece-part exposure. The agency is proposing this AD “to prevent the inability to restart both engines after flameout due to excessive friction of the four-step seal, which could result in subsequent forced landing of the airplane.”