Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for all CFM56-3 and CFM56-7B series turbofan engines with certain accessory gearboxes (AGBs) not equipped with a handcranking pad "oil dynamic seal" assembly. This proposed AD was prompted by 42 events of total loss of engine oil from CFM56 series turbofan engines while in flight. This proposed AD would require an independent inspection to verify re- installation of the handcranking pad cover after removal of the pad cover for maintenance until installation of a handcranking pad oil dynamic seal assembly. This inspection requirement exceeds normal maintenance and is necessary due to the design and location of the handcranking pad cover on the accessory gear box. We are proposing this AD to prevent loss of engine oil while in flight, which could result in engine failure, loss of thrust control, and damage to the airplane.