82-14-02 PRATT & WHITNEY AIRCRAFT: Amendment 39-4411. Applies to all Pratt & Whitney Aircraft JT3D turbofan engines.
Compliance required as indicated, unless already accomplished.
To detect cracks in third stage turbine disks, P/Ns 418903, 438903, and 675803, which could result in fracture of the third stage turbine disk and an uncontained third stage turbine disk failure, inspect third stage turbine disks, P/Ns 438903 and 675803, for cracks in the tierod holes, counterweight holes, and spacer snap diameter fillet radii. Inspect in accordance with Pratt & Whitney Aircraft Alert Service Bulletin No. 5358, dated February 5, 1982, or later FAA approved revision, or equivalent means approved by the Chief, Engine Certification Branch, Federal Aviation Administration, New England Region, per the following schedule:
a. Disks with less than 4,500 cycles on the effective date of this AD shall be inspected before 5,500 cycles.
b. Disks with between 4,500 and 4,999 cycleson the effective date of this AD shall be inspected within 1,000 cycles.
c. Disks with between 5,000 and 5,500 cycles on the effective date of this AD shall be inspected before 6,000 cycles.
d. Disks with more than 5,500 cycles on the effective date of this AD shall be inspected within 500 cycles.
Cracked third stage turbine disks cannot be continued in service. Any third stage turbine disk which has a crack which is within the allowable crack repair limit(s) specified in the above referenced Pratt & Whitney Aircraft Alert Service Bulletin may be returned to service if it is repaired in accordance with this service bulletin. Any third stage turbine disk which has had all of the tierod holes and all of the counterweight holes repaired in accordance with this service bulletin must be reinspected in accordance with the service bulletin prior to the accumulation of 4,000 additional cycles after inspection. All other third stage turbine disks which are suitable for continued usage per this service bulletin must be reinspected in accordance with this service bulletin prior to the accumulation of 2,500 additional cycles after inspection. These repetitive inspections must be repeated throughout the service life of the third stage turbine disk.
Third stage turbine disks, P/N 418903, shall be removed from service within 500 cycles from the effective date of this AD or by December 31, 1982, whichever comes first. The inspection and rework provisions of Pratt & Whitney Aircraft Alert Service Bulletin No. 5358 do not apply to P/N 418903 third stage turbine disks.
NOTE: The established life limits for the third stage turbine disks shall not be exceeded.
Upon request of the operator, an FAA Maintenance Inspector, subject to prior approval of Chief, 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.
All persons affected by this directive who have not already received the referenced Alert Service Bulletin from the manufacturer may obtain copies upon request to Pratt & Whitney Aircraft, Division of United Technologies Corporation, 400 Main Street, East Hartford, Connecticut 06108. This document may also be examined at Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803. A historical file on this AD is maintained by the FAA at the New England Region Office.
This amendment becomes effective on July 1, 1982.