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Notice of proposed rulemaking (NPRM).

We propose to adopt a new airworthiness directive (AD) for all Honeywell International, Inc. ALF502L-2C; ALF502R-3; ALF502R-3A; ALF502R-5; LF507-1F; and LF507-1H turbofan engines. This proposed AD was prompted by two reports of engines experiencing uncontained release of low-pressure (LP) turbine blades. This proposed AD would require operational checks of the engine overspeed trip system. We are proposing this AD to prevent LP turbine overspeed leading to uncontained release of the LP turbine blades and damage to the airplane.

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