78-17-02 R3 PRATT & WHITNEY AIRCRAFT: Amendment 39-3281 as amended by Amendment 39-4334 and 39-4407 is further amended by Amendment 39-4818. Applies to Pratt & Whitney Aircraft models JT8D-9, - 9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan engines.
Compliance is required as indicated, unless already accomplished.
To detect cracks in compressor front hubs, P/Ns 594301, 791801, 640601, 743301, 750101, and 749801, except those excluded by serial number in Pratt & Whitney Aircraft Alert Service Bulletin No. 4841, Revision 6, dated July 15, 1983, which could result in fracture of the retention lugs and release of first stage fan blades, accomplish the following:
(A) Inspect front compressor front hubs for cracks in the blade slots in accordance with Pratt & Whitney Aircraft Alert Service Bulletin No. 4841, Revision 6, dated July 15, 1983, or equivalent means approved by the Manager, Engine Certification Branch, New England Region, and in accordance with limits specified in Paragraphs (B) and (C) of this AD. Remove cracked compressor front hubs prior to further flight.
(B) Hubs not previously inspected shall be inspected within 1,000 cycles from the effective date of this AD or before reaching the initial inspection limits specified in Column I of Paragraph (D), whichever occurs later, except do not exceed 13,000 total cycles. Repeat inspections at intervals listed in Column II, or Column III, Paragraph (D), thereafter.
(C) Hubs which have been previously inspected shall be reinspected within 1,000 cycles after the effective date of this AD or before reaching the initial inspection limit specified in Column I, Paragraph (D), or before reaching the repetitive inspection limits specified in Column II or Column III of Paragraph (D), whichever comes later. Repeat inspections at intervals listed in Column II or Column III, Paragraph (D), thereafter.
(D)
Model
Column I, initial inspection limit
(cycles)
Column II, Eddy
current repetitive
inspection limit
(cycles)
Column III, on-wing
ultrasonic repetitive
repetitive inspection
limit (cycles)
JT8D-9, -9A
13,000
6,000
2,000
JT8D-11
10,500
6,000
2,000
JT8D-15, -15A
9,500
5,000
1,500
JT8D-17, -17A
8,500
5,000
1,500
JT8D-17R, -17AR
8,000
5,000
1,500
NOTE: If the initial inspection or repetitive inspection is in paragraph (D) apply. If, however, the initial inspection or repetitive inspection is achieved by an eddy current inspection on an uninstalled engine, the Column II inspection limits of paragraph (D) would apply.
(E) Upon request of the operator, an FAA maintenance inspector, subject to the approval of the Manager, Engine Certification Branch, FAA, New England Region, may adjust the inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.
(F) For hubs that have been installed in more than one engine model, the inspection schedule for the engine model with the highest thrust rating in which it has operated is applicable.
The manufacturer's Alert Service Bulletin identified and described in this directive is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a). All persons affected by this directive who have not already received the service bulletin from the manufacturer may obtain copies upon request to Pratt & Whitney Aircraft, Commercial Products Division, 400 Main Street, East Hartford, Connecticut 06108. The service bulletin may also be examined at Federal Aviation Administration, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, Massachusetts 01803.
Amendment 39-3281 became effective September 20, 1978.
Amendment 39-4334 became effective March 4, 1982.
Amendment 39-4407 became effective June 28, 1982.
This Amendment 39-4818 becomes effective March 30, 1984.