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2015-21-04: 6th stage low-pressure turbine (LPT) disk

FAA order 2015-21-04 is an airworthiness directive in force since November 27, 2015. The FAA's subject line: 6th stage low-pressure turbine (LPT) disk. It names the Pratt & Whitney PW4168A engine: about 12 aircraft on the U.S. register today, though an order usually covers particular versions or serial numbers rather than every one. System: engine.

What it applies to as the FAA lists it

Kind of product
Engine
Makes
Pratt & Whitney Division
Models
PW4164, PW4164-1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D, PW4170
Engine series
Pratt & Whitney PW4168A 12 aircraft

Dates and paperwork

In force since
November 27, 2015
Published
October 23, 2015 (signed October 9, 2015)
Docket
FAA-2015-0869
Status
Current
The FAA's document
Read the order on the FAA's site

The FAA's summary their words, unchanged

We are adopting a new airworthiness directive (AD) for certain Pratt & Whitney (PW) PW4164, PW4168, PW4168A, PW4164-1D, PW4168-1D, PW4168A-1D, and PW4170 turbofan engines. This AD was prompted by crack finds in the 6th stage low-pressure turbine (LPT) disk. This AD requires [[Page 64313]] removal of the affected 6th stage LPT disks. We are issuing this AD to prevent failure of the 6th stage LPT disk, which could lead to an uncontained disk release, damage to the engine, and damage to the airplane.

The order itself the regulatory text, as published

Show the full text (3,381 characters)
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): 2015-21-04 Pratt & Whitney: Amendment 39-18296; Docket No. FAA-2015- 0869; Directorate Identifier 2015-NE-11-AD. [[Page 64314]] (a) Effective Date This AD is effective November 27, 2015. (b) Affected ADs None. (c) Applicability This AD applies to all Pratt & Whitney (PW) PW4164, PW4168, PW4168A, PW4164-1D, PW4168-1D, PW4168A-1D, and PW4170 turbofan engines with 6th stage low-pressure turbine (LPT) disks, part number 50N886, installed. (d) Unsafe Condition This AD was prompted by crack finds in the 6th stage LPT disk. We are issuing this AD to prevent failure of the 6th stage LPT disk, which could lead to an uncontained disk release, damage to the engine, and damage to the airplane. (e) Compliance Comply with this AD within the compliance times specified, unless already done. At the next LPT shop visit after the effective date of this AD, remove from service 6th stage LPT disks with serial numbers listed in the Accomplishment Instructions, Table 1, of PW Service Bulletin No. PW4G-100-72-252, dated November 18, 2014. (f) Definition For the purpose of this AD, an ``LPT shop visit'' is defined as the removal of the 6th stage disk from the LPT rotor and the removal of the blades from the disk. (g) Alternative Methods of Compliance (AMOCs) The Manager, Engine Certification Office, FAA, may approve AMOCs for this AD. Use the procedures found in 14 CFR 39.19 to make your request. You may email your request to: ANE-AD-AMOC@faa.gov. (h) Related InformationFor more information about this AD, contact Besian Luga, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: 781-238-7750; fax: 781-238-7199; email: besian.luga@faa.gov. (i) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. (3) The following service information was approved for IBR on November 27, 2015. (i) Pratt & Whitney (PW) Service Bulletin No. PW4G-100-72-252, dated November 18, 2014. (ii) Reserved. (4) For PW service information identified in this AD, contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; phone: 860- 565-8770; fax: 860-565-4503. (5) You may view this service information at FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125. (6) You may view this service information at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of October 7, 2026. Connections as data: /graph/directive/2015-21-04.json · aircraft systems.