AD 89-24-02

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AD Number:
89-24-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
PRATT & WHITNEY Models JT8D-7, -7A, and -7B Engines
Subject:
Fan Disk
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
11/13/1989
Make:
Pratt & Whitney Division
Model:
JT8D-7 | JT8D-7A | JT8D-7B
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 89-24-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-6365

AD NUMBER:   89-24-02

SUBJECT HEADING:   PRATT & WHITNEY Models JT8D-7, -7A, and -7B Engines

ACTION:  

SUMMARY:  

DATES:   Effective November 13, 1989.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
89-24-02 PRATT & WHITNEY: Amendment 39-6365.

Applicability: Pratt & Whitney (PW) JT8D-7, -7A, and -7B turbofan engines.

Compliance: Required as indicated, unless already accomplished.

To prevent engine failure, cowl penetration, fire, or airframe damage associated with a second stage fan disk fracture, accomplish the following:

(a) Visually inspect for the presence and protrusion of a spacer within 100 cycles in service (CIS) after the effective date of this AD. NOTE (1) defines the spacer location. If a spacer is found during inspection, accomplish the following:

(1) If the spacer radial protrusion is in excess of 0.125 inches, trim the spacer to the fan case inner flow surface.

(2) If the spacer radial protrusion is in excess of 0.250 inches over a circumferential length greater than 3 inches, remove the second stage fan disk, first stage stator assembly, and the spacer. Inspect the disk in accordance with paragraphs (d)(1), (d)(2), and (d)(3), within 100 CIS after inspection and thereafter, reinspect the disk in accordance with paragraph (e).

(b) Thereafter, visually reinspect for first stage stator spacer protrusion, if a spacer is installed, in accordance with the limits noted in paragraphs (a)(1) and (a)(2), at intervals not to exceed 200 CIS since last inspection (SLI) and until the first stage stator assembly and spacer are removed per paragraph (c) below.

(c) Remove the first stage stator assembly and spacer, and install a new or a refurbished first stage stator assembly in accordance with PW JT8D Engine Manual, Part Number (P/N) 481672, at the next engine shop visit, but no later than 4,000 CIS after the effective date of this AD.

(d) Inspect all second stage fan disks which have operated in an engine with a spacer installed at the next engine shop visit, but no later than 4,000 CIS after the effective date of this AD, or as required by paragraph (a)(2) above. The inspection shall include the following:

(1) Eddy current inspect disk pin holes and remove from service all disks defined as not serviceable in accordance with the instructions in the APPENDIX (United Airlines Eddy Current Non-Destructive Test Procedure Number MJ-70-NDT-352, dated June 6, 1989) to this AD.

(2) Visually inspect the inner surface of the disk pin hole for evidence of galling or other surface damage. Reject disks with damage in excess of 0.003 inches deep.

(3) Dimensionally inspect the disk pin hole diameters. Reject disks if any disk pin hole diameter exceeds 0.5498 inches (Reference PW JT8D Engine Manual, Section 72-33-04, Inspection -01, Page 801, Reference 222).

(e) Thereafter, reinspect second stage fan disks in accordance with paragraphs (d)(1), (d)(2), and (d)(3) above, at intervals not to exceed 4,000 CIS SLI if the disk operated in an engine with a spacer radial protrusion in excess of the limits established in paragraph (a)(2) above.

(f) If a first stage stator spacer is found during the initial visual inspection, report the following information in writing within 30 days of the inspection to the Manager, Engine Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803; Telex Number 949301 FAANE BURL:

(1) Engine serial number (S/N).

(2) Inspection date.

(3) First stage stator spacer maximum radial protrusion and circumferential length of protrusion.

(4) Second stage fan disk P/N and S/N.

(g) Report the following information in writing within 30 days of the second stage fan disk inspection to the Manager, Engine Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803; Telex Number 949301 FAANE BURL:

(1) Engine serial number (S/N).

(2) Inspection date.

(3) Second stage fan disk P/N and S/N.

(4) Second stage fan disk total time and cycles (if estimate, so note).

(5) Second stage fan disk time and cycles since installation.

(6) Second stage fan disk inspection results for rejected disks (specify rejection criteria used).

Information collection requirements contained in this regulation (Section 39.13) have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (Pub. L. 96-511) and have been assigned OMB Control Number 2120-0056.

(h) Records showing that United Airlines (UAL) has not performed maintenance on the engine may be used in lieu of the visual inspection requirements of paragraph (a) above to verify the absence of the spacer, provided the operator's FAA Airworthiness Inspector is supplied with a complete maintenance history of the engine and determines that UAL has never maintained, overhauled or altered the engine after October 10, 1972.

NOTES: (1) The location where the first stage stator spacer would be installed is shown in the PW JT8D Engine Manual, P/N 481672, Section 72-33-65, Repair-00, Page 901/902, Figure 901, Index 3.

(2) Engine shop visit is defined as the input of an engine to a repair shop with low pressure compressor rotor overhaul capability where the subsequent engine maintenance entails the following:

(a) Separation of a major engine flange (lettered or numbered) other than flanges mating with major sections of the nacelle or reverser. Separation of flanges purely for purposes of shipment, without subsequent internal maintenance, is not a "shop visit."

(b) Removal of a disk, hub, or spool.

(i) Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.

(j) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance with the requirements of this AD or adjustments to the compliance times specified in this AD, may be approved by the Manager, Engine Certification Office, ANE-140, Engine and Propeller Directorate, Aircraft Certification Service, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803.

This amendment (39-6365, AD 89-24-02) becomes effective on November 13, 1989.

89-24-02 APPENDIX
NOTE: United Airlines Eddy Current Non-Destructive Test Procedure Number MJ-70-NDT-352, dated June 6, 1989, pertain to these inspections.

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