# AD 73-07-08: Fuel Control To Fuel Return Line Elbow and Jam Nut

- Type: Airworthiness directive
- Status: Current
- Products: Pratt & Whitney Division JT3D-1, JT3D-1-MC6, JT3D-1-MC7, JT3D-3 and JT3D-3B
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-1630
- Registered aircraft: 5 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/99FE06404B2C3CD986256E0D00478B53.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/73-07-08

## The airworthiness directive

73-07-08 PRATT & WHITNEY: Amendment 39-1616 as amended by Amendment 39-1630. Applies to all Pratt & Whitney JT3D-1, JT3D-1-MC6, JT3D-1-MC7, JT3D-3 and JT3D-3B model engines containing fuel control to fuel return line elbow P/N 424790 and jam nut P/N 217477.

Compliance required within the next 500 hours time in service after the effective date of this AD and every 1000 hours in service thereafter, or until modified in accordance with the service bulletin referenced in paragraph (b)(2) or equivalent method approved by the Chief, Engineering and Manufacturing Branch, New England Region.

To prevent the possibility of fuel leakage due to loosening of fuel control to fuel pump return tube elbow P/N 424790, and jam nut P/N 217477, check jam nut torque value.

  (a) If found to be a minimum of 285 in-lbs., continue in service operation.

  (b) If the jam nut is found to be less than 285 in-lbs., break the connection and examine the mating threads of the elbow P/N 424790 and fuel control cover P/N 704972-1 on their loaded sides for wear.

NOTE: The loaded side will be on the fuel side (inside) rather than the air side (outside) of the cover.

  (1) If the threads are not worn remake the fitting according to the instructions given in the Overhaul Manual, P/N 411568, Section 72-00, Fits and Clearances.

  (2) If the threads of the elbow. P/N 424790, or fuel control cover P/N 704972-1, are found worn replace with new or serviceable parts of same part number or with P/N 483848 elbow and associated hardware in accordance with Pratt & Whitney Service Bulletin No. 1511 Revision 4, dated June 20, 1969, or later FAA approved revision.

  (c) Upon submission of substantiating data through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, New England Region, may adjust repetitive inspection intervals specified in this AD.

Amendment 39-1616 became effective April 11, 1973.

This amendment 39-1630 becomes effectiveupon publication in the Federal Register.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1E8](https://openairdocs.org/tcds/1E8): Pratt & Whitney Division; names 5 of 11 models: JT3D-3, JT3D-1-MC6, JT3D-1-MC7, JT3D-3B, JT3D-1

## 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: 5 (0 by airframe model, 5 by engine model)
- Makers: Boeing 3, Mcdonnell Douglas 2

Models with the most aircraft:

- [Pratt & Whitney JT3D-3B](https://openairdocs.org/engine/pratt-whitney-jt3d-3b): 3 aircraft (engine model)
- [Pratt & Whitney JT3D series](https://openairdocs.org/engine/pratt-whitney-jt3d-series): 2 aircraft (engine model)

All 2 models: https://openairdocs.org/ad/73-07-08/models.md
Every aircraft: https://openairdocs.org/ad/73-07-08/aircraft.md

Its text cites no advisory circulars or STCs.

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