# AD 71-06-03: Twelfth Stage Compressor Rotor Disc

- Type: Airworthiness directive
- Status: Current
- Products: Pratt & Whitney Division JT4A-10, JT4A-11, JT4A-12, JT4A-3, JT4A-5 and JT4A-9
- Effective: May 19, 1971
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-1211
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/481B5BC84BC66FCD86256E01005AD187.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/71-06-03

## The airworthiness directive

71-06-03 PRATT & WHITNEY: Amdt. 39-1168 as amended by Amendment 39-1211. Applies to all Pratt & Whitney Aircraft JT4A series turbojet engines which incorporate the following serial number 12th stage compressor rotor disc part number 360112.

2G5181 2G6360

2G5182 2G6362

2G5183 2G6363

2G5446 2G6445

2G5807 2G6448

2G5812 2G6449

2G5818 2G6454

2G5820 2G6581

2G5821 2G6583

2G5825 2G6585

2G5826 3G0201

2G6027

2G6030

5F7645 7

5F858 6F8362 5F7646

5F8588 6F9707 5F8544 through

5F8695 6F9739 5F8547

6F7206 6F9751 5F8550 through

6F7207 6F9753 through 5F8553

6F7210 6F9759 5F8558

6F7214 6F9760 through 5F8576

6F7218 6F9765 5F8577

6F7501 6F9846 5F8581 through

6F7502 6F9853 5F8584

6F7504 6F9861

6F7949 6F9866

6F8168 7F0156

6F8198 7F0480

7F0556

Pratt & Whitney Aircraft telegram PSE/RS/1-3-10-1 covers this same subject.

Compliance required as indicated.

To preclude twelfth stage compressor rotor disc failure as the result of suspected material deficiency, accomplish the following:

1. For all the previously listed serial number twelfth stage compressor rotor discs:

A. With 18,000 hours or more in service within the next 50 hours in service after the effective date of this AD, replace the suspect serial number disc.

B. With 18,000 hours or less in service prior to the accumulation of 18,050 hours in service, replace the suspect serial number disc.

2. Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, may adjust the compliance time.

Amendment 39-1168 was effective March 12, 1971.

This amendment 39-1211 is effective May 19, 1971 and was effective for all recipients of the telegram dated March 12, 1971 which contained this amendment.

## 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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