EASA AD US-2018-21-11
SUPERSEDED BY FAA AD 2023-19-02
Summary
FAA Airworthiness Directive 2018-21-11 is a final rule addressing Pratt & Whitney PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines equipped with low-pressure compressor (LPC) fan hubs, part numbers 51B821 or 52B521. The directive mandates repetitive eddy current and fluorescent penetrant inspections to detect cracks in these LPC fan hubs to prevent premature failure. This AD aims to enhance safety by mitigating the risk of uncontained fan hub release and subsequent engine or aircraft damage.
What Changed
This new airworthiness directive introduces mandatory repetitive inspections for specific LPC fan hubs on affected Pratt & Whitney engines based on updated low-cycle fatigue analysis. It requires removal from service of any fan hub that fails inspection. The AD clarifies inspection procedures and maintains existing life limits without adding maximum allowable life limits.
Why It Matters
This AD is critical for aviation professionals as it addresses a potential unsafe condition that could lead to catastrophic engine failure. Operators and maintenance organizations must implement the inspection requirements to ensure continued airworthiness and compliance with FAA regulations. Failure to comply could result in uncontained engine damage and compromise flight safety.
What To Do
Operators of affected Pratt & Whitney PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 engines must perform repetitive eddy current and fluorescent penetrant inspections of LPC fan hubs, part numbers 51B821 or 52B521, starting by the effective date of December 5, 2018. Any fan hub found cracked must be removed from service immediately. Compliance with the inspection intervals and removal criteria specified in the AD and referenced service bulletins is mandatory.
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