airworthiness · Rule · Final rule. · Published 2012-09-06 · Effective 2012-10-11 · 77 FR 54791
Document
Document number
2012-21821
Federal Register citation
77 FR 54791
Type
Rule
Action
Final rule.
Category
airworthiness
Manufacturer
Pratt & Whitney Division Turbofan
Publication date
2012-09-06
Effective date
2012-10-11
FAA docket
Docket No. FAA-2012-0228
Abstract
We are adopting a new airworthiness directive (AD) for certain Pratt & Whitney Division PW4000-94" and PW4000-100" turbofan engines having a 1st stage high-pressure turbine (HPT) seal support, part number (P/N) 55K601 (contained within assembly P/N 55K602-01) or P/N 50K532 (contained within assembly P/N 50K530-01), installed. This AD was prompted by 58 reports of cracked 1st stage HPT air seal rings, including 15 in-flight engine shutdowns. This AD requires removal and replacement of the 1st stage HPT seal support and inspection of the 1st stage HPT air seal ring. We are issuing this AD to prevent failure of the 1st stage HPT air seal ring, which could lead to an internal oil fire, uncontained engine failure, and damage to the airplane.