78-08-07 PRATT & WHITNEY AIRCRAFT: Amendment 39-3175. Applies to Pratt & Whitney Aircraft Wasp, Jr. and R985 model engines.
Compliance required as indicated, unless already accomplished.
To prevent cylinder head separation from the barrel, perform the following in accordance with Pratt & Whitney Aircraft Service Bulletin No. 1785 or later FAA-approved revision.
1. Visually inspect cylinder heads in accordance with Part B of the bulletin as follows:
A. Cylinders not ultrasonically inspected, inspect within 50 hours time in service after effective date of the AD, and thereafter at intervals not to exceed 100 hours time in service.
B. Cylinders ultrasonically inspected, inspect within 150 hours time in service after effective date of the AD, and thereafter at intervals not to exceed 150 hours time in service.
2. Remove visibly cracked cylinders and cylinders with black combustion leakage from service before further flight.
3. After the effective date of this AD, inspect all cylinder assemblies, prior to installation on an engine, by the ultrasonic test procedure in Part A of Service Bulletin 1785 or equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, New England Region.
4. Remove from service cylinders which show cracks in excess of the limits of Part A, Section IV, of the bulletin.
NOTE: Cylinders which have been ultrasonically tested are stamped "UT" and last two digits of year inspected over the intake port.
The manufacturer's service bulletin identified and described in this directive is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received this document from the manufacturer may obtain copies upon request to Pratt & Whitney Aircraft, Division of United Technologies Corp., 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, and FAA Headquarters, 800 Independence Avenue SW., Washington, D.C. 20591.
This supersedes AD 76-20-01, Amendment 39-2728.
This amendment becomes effective May 2, 1978.