Action
Final rule.
Summary
The FAA is superseding Airworthiness Directive (AD) 2018-02- 10, which applied to certain Pratt & Whitney Division (PW) Model PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines. AD 2018-02-10 required performing repetitive fluorescent penetrant inspections (FPIs) to detect cracks in the outer diffuser case (ODC), removal of any ODC that fails inspection, and updating the mandatory inspections in the Airworthiness Limitations Section (ALS) of the Instructions for Continued Airworthiness (ICA). Since the FAA issued AD 2018-02-10, PW developed a modification to reduce the susceptibility of ODC cracking. This AD retains the ALS update requirement from AD 2018-02-10, requires replacing certain ODC part numbers with parts eligible for installation, expands the applicability to all ODC part numbers, and adjusts the compliance threshold of the FPIs of the ODC. The FAA is issuing this AD to address the unsafe condition on these products.