2012-06-14: HPT 1st stage air seals

Adoption of the Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39--AIRWORTHINESS DIRECTIVES 0 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. Sec. 39.13 [Amended] 0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): 2012-06-14 Pratt & Whitney: Amendment 39-16995; Docket No. FAA-2011- 1176; Directorate Identifier 2011-NE-35-AD. (a) Effective Date This AD is effective April 27, 2012. (b) Affected ADs None. (c) Applicability This AD applies to Pratt & Whitney JT9D-7R4G2 and -7R4H1 turbofan engines. (d) Unsafe Condition This AD was prompted by the determination that a new lower life limit of 9,000 cycles-since-new (CSN) for high-pressure turbine (HPT) 1st stage air seals, part number (P/N) 735907, is necessary. We are issuing this ADto prevent critical life-limited rotating engine part failure, and damage to the airplane. (e) Compliance Comply with this AD within the compliance times specified, unless already done. (f) Removal of HPT 1st Stage Air Seals, P/N 735907 Remove HPT 1st stage air seals, P/N 735907, from service as follows: (1) For air seals that have fewer than 6,500 CSN on the effective date of this AD, remove the air seals from service before exceeding 9,000 CSN. (2) For air seals that have 6,500 CSN or more on the effective date of this AD, do the following: (i) If the engine has a shop visit before the air seal exceeds 9,000 CSN, remove the air seal from service before exceeding 9,000 CSN. (ii) If the engine does not have a shop visit before the air seal exceeds 9,000 CSN, remove the air seal from service at the next shop visit, not to exceed 2,500 cycles from the effective date of this AD or 15,000 CSN, whichever occurs first. (g) Installation Prohibition(1) After the effective date of this AD, do not install or reinstall into any engine any HPT 1st stage air seal, P/N 735907, removed from service in accordance with paragraph (f) of this AD. (2) After the effective date of this AD, do not install or reinstall into any JT9D-7R4G2 or JT9D-7R4H1 engine any HPT 1st stage air seal, P/N 735907, that exceeds the new life limit of 9,000 CSN. (h) Engine Shop Visit Definition For the purposes of this AD, an engine shop visit is the induction of an engine into the shop after the effective date of this AD, where the separation of a major engine flange occurs, except that the following maintenance actions, or any combination thereof, are not considered engine shop visits: (1) Introduction of an engine into a shop solely for removal of the compressor top or bottom case for airfoil maintenance or variable stator vane bushing replacement. (2) Introduction of an engine into a shop solely for removal or replacement of the stage 1 fan disk. (3) Introduction of an engine into a shop solely for replacement of the turbine rear frame. (4) Introduction of an engine into a shop solely for replacement of the accessory gearbox or transfer gearbox, or both. (5) Introduction of an engine into a shop solely for replacement of the fan containment case. (i) Alternative Methods of Compliance (AMOCs) The Manager, Engine Certification Office, may approve AMOCs for this AD. Use the procedures found in 14 CFR 39.19 to make your request. (j) Related Information For more information about this AD, contact Ian Dargin, Aerospace Engineer, Engine & Propeller Directorate, FAA, 12 New England Executive Park, Burlington, MA 01803; phone: 781-238-7178; fax: 781-238-7199; email: ian.dargin@faa.gov. (k) Material Incorporated by Reference None.