# AD 78-08-07: Cylinder Head Separation - Type: Airworthiness directive - Status: Current - Products: Pratt & Whitney Division Military R-985 Series, Wasp Jr. A, Wasp Jr. B-4, Wasp Jr. B-5, Wasp Jr. SB, Wasp Jr. SB-2, Wasp Jr. SB-3, Wasp Jr. T1B, Wasp Jr. T1B2, Wasp Jr. T1B3, Wasp Jr. T3A, Wasp Jr. TB and 1 more - Effective: May 2, 1978 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-3175 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1B69E8B0A40E24F88625682C0057E15D.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/78-08-07 ## The airworthiness directive 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. ## Affected data sheets (5) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E-123](https://openairdocs.org/tcds/E-123): Pratt & Whitney Division; names 7 of 7 models: Wasp Jr. T1B3, Wasp Jr. B-4, Wasp Jr. SB-3, Wasp Jr. T1B2, Wasp Jr. SB, Wasp Jr. SB-2, Wasp Jr. B-5 - [TCDS TC 85](https://openairdocs.org/tcds/TC%2085): Pratt & Whitney Division; names 3 of 3 models: Wasp Jr. TB, Wasp Jr. TB-2, Wasp Jr. T3A - [TCDS ATC 39](https://openairdocs.org/tcds/ATC%2039): Pratt & Whitney Division; names 1 of 1 models: Wasp Jr. A - [TCDS TC 113](https://openairdocs.org/tcds/TC%20113): Pratt & Whitney Division; names 1 of 1 models: Wasp Jr. T1B - [TCDS TC 5E-1](https://openairdocs.org/tcds/TC%205E-1): Pratt & Whitney Division; names 1 of 1 models: Military R-985 Series ## Registered aircraft it may apply to (OpenAirDocs) No registered aircraft matched the models it names. Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (3) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB WPR16LA082](https://openairdocs.org/ntsb/WPR16LA082), Mar 12, 2016: Grumman G164 (N6894Q), Juliaetta, ID, substantial damage. Probable cause: A partial loss of engine power due to a crack in the No. 2 cylinder. - [NTSB CHI01LA286](https://openairdocs.org/ntsb/CHI01LA286), Aug 16, 2001: Grumman-Schweizer G-164A (N4598), Petersburg, NE, substantial damage. Probable cause: The failure of the engine cylinder, and the unsuitable terrain for landing encountered by the pilot. Factors were the low altitude and the muddy field. - [NTSB ATL97FA095](https://openairdocs.org/ntsb/ATL97FA095), Jul 2, 1997: Boeing Stearman B75N1 (N450GC), Locust Grove, GA, destroyed, 1 fatal. Probable cause: The inadvertent stall encountered by the pilot after experiencing an in-flight cylinder head separation. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.