# AD 73-16-05: Fourth and Fifth Stage Turbine Discs

- Type: Airworthiness directive
- Status: Current
- Products: Pratt & Whitney Division JT9D-20, JT9D-20J, JT9D-3A, JT9D-59A, JT9D-7, JT9D-70A, JT9D-7A, JT9D-7AH, JT9D-7F, JT9D-7H, JT9D-7J, JT9D-7Q and 8 more
- Effective: August 15, 1973
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-1698
- Registered aircraft: 24 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/12EC0882CDCFB1398625685B0068D47F.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/73-16-05

## The airworthiness directive

73-16-05 PRATT & WHITNEY: Amdt. 39-1698. Applies to all Pratt and Whitney Aircraft JT9D turbofan engines containing fourth and fifth stage turbine discs, P/N 646304, 694804, 618305, and 705905.

Compliance required as indicated.

To prevent possible failure of fourth and fifth stage turbine discs, the life limits on these parts have been reduced below the figures currently approved. Unless already accomplished, remove from service fourth and fifth stage turbine discs prior to reaching the revised life limit listed below or within the next 25 cycles in service after the effective date of this airworthiness directive whichever comes later.

Disc Part Number Previous Life Limit Cycles Revised Life Limit Cycles 646304 8000 4000 694804 8000 4000 618305 8000 4000 705905 8000 4000

(Upon submission of substantiating data through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, New England Region, may adjust the compliance time).

NOTE: (Pratt and Whitney Service Bulletin No. 3785 pertains to this subject).

This amendment becomes effective August 15, 1973.

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E3NE](https://openairdocs.org/tcds/E3NE): Pratt & Whitney; names 11 of 11 models: JT9D-7Q, JT9D-7Q3, JT9D-7R4E4, JT9D-7R4E, JT9D-70A, JT9D-7R4H1, JT9D-7R4D1, JT9D-7R4D…
- [TCDS E20EA](https://openairdocs.org/tcds/E20EA): Pratt & Whitney; names 9 of 9 models: JT9D-7, JT9D-7AH, JT9D-7J, JT9D-3A, JT9D-7F, JT9D-7A, JT9D-20, JT9D-7H…

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 24 (0 by airframe model, 24 by engine model)
- Makers: Boeing 19, Airbus Industrie 2, Douglas 2, Mcdonnell Douglas 1

Models with the most aircraft:

- [Pratt & Whitney JT9D series](https://openairdocs.org/engine/pratt-whitney-jt9d-series): 13 aircraft (engine model)
- [Pratt & Whitney JT9D-7R4D](https://openairdocs.org/engine/pratt-whitney-jt9d-7r4d): 4 aircraft (engine model)
- [Pratt & Whitney JT9D-3A](https://openairdocs.org/engine/pratt-whitney-jt9d-3a): 4 aircraft (engine model)
- [Pratt & Whitney JT9D-7](https://openairdocs.org/engine/pratt-whitney-jt9d-7): 1 aircraft (engine model)
- [Pratt & Whitney JT9D-59A](https://openairdocs.org/engine/pratt-whitney-jt9d-59a): 1 aircraft (engine model)
- [Pratt & Whitney JT9D-7R4E](https://openairdocs.org/engine/pratt-whitney-jt9d-7r4e): 1 aircraft (engine model)

All 6 models: https://openairdocs.org/ad/73-16-05/models.md
Every aircraft: https://openairdocs.org/ad/73-16-05/aircraft.md

Its text cites no advisory circulars or STCs.

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