# AD 76-01-08: Tenth Stage Compressor Blade

- Type: Airworthiness directive
- Status: Current
- Products: Pratt & Whitney Division JT4A-10, JT4A-11, JT4A-12, JT4A-3, JT4A-5 and JT4A-9
- Effective: May 20, 1976
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-2603
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F507FC6178EBC38986256E0D00478D04.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/76-01-08

## The airworthiness directive

76-01-08 PRATT & WHITNEY AIRCRAFT: Amendment 39-2492 as amended by Amendment 39-2603. Applies to all Pratt & Whitney Model JT4A turbojet engines containing tenth stage compressor blades, P/N 499710 and P/N 310010.

To prevent possible tenth stage compressor blade failure resulting in case penetration, shotpeen the blades in accordance with JT4A Overhaul Manual, P/N 384887, Section 72-36-1, and apply antigalling compound in accordance with TR 72-617, of JT4A Overhaul Manual P/N 384887, in accordance with the following schedule:

1. Within 4000 hours time in service since the last shotpeening to 6A intensity or within 2000 hours time in service since January 28, 1976, whichever is later, and every 4000 hours time in service thereafter.

2. Within 6000 hours time in service since the last shotpeening to 11A intensity or 2000 hours after January 28, 1976, whichever is later and every 6000 hours time in service thereafter.

3. Blades that have never been shotpeened must be shotpeened within 2000 hours time in service since January 28, 1976, and are subsequently subject to the repetitive shotpeening requirements of paragraphs 1 and 2.

Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA, New England Region, may adjust the repetitive shotpeen 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.

The manufacturer's specifications and procedures identified and described in this directive are 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 these documents from the manufacturer may obtain copies upon request to Pratt & Whitney Aircraft, Division of United Aircraft Corporation, 400 Main Street, East Hartford, Connecticut 06108. These documents may also be examined at Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, and at FAA headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD which includes the incorporated material in full is maintained by the FAA at its headquarters in Washington, D.C., and at New England Region.

Amendment 39-2492 became effective on January 28, 1976.

This amendment 39-2603 becomes effective May 20, 1976.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E-291](https://openairdocs.org/tcds/E-291): Pratt & Whitney Division; names 6 of 6 models: JT4A-11, JT4A-3, JT4A-9, JT4A-10, JT4A-5, JT4A-12

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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