# AD 73-15-02: Turbine Case Lug

- Type: Airworthiness directive
- Status: Current
- Products: Pratt & Whitney Division JT3D-1, JT3D-1-MC6, JT3D-1-MC7, JT3D-3 and JT3D-3B
- Effective: September 14, 1973
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-1712
- Registered aircraft: 5 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B31EC07A31D20B4386256E0D00478BB7.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/73-15-02

## The airworthiness directive

73-15-02 PRATT & WHITNEY: Amdt. 39-1687 as amended by Amendment 39-1712. Applies to all JT3D-1, JT3D-1-MC6, JT3D-1-MC7, JT3D-3 and JT3D-3B model engines containing turbine nozzle case Part Numbers 399065, 496859, 570618, 626669, 669045, 669047, 694937, 694938, 390197, 694935 and 691326 incorporating vented 2nd stage outer airseals.

Compliance required as follows:

To preclude possible turbine blade or disc failures resulting from turbine case lug failures, inspect the turbine nozzle case for missing lugs by performing Ultrasonic, Isotope or Visual inspection at the time intervals specified below.

First inspection, 1,000 hours time in service after the effective date of this AD unless already accomplished.

  (a) If there are no missing lugs, repeat the inspection every 1,000 hours time in service thereafter.

  (b) If one lug is found missing, repeat the inspection every 100 hours time in service.

  (c) If two or three lugs are found missing, remove the engine within the next 50 hours time in service.

  (d) If four or more lugs are missing, remove from service immediately.

Turbine cases may be repaired in accordance with the procedures outlined in the Overhaul Manual, Section 72-51-2, or replaced.

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 & Whitney Service Bulletin 3993, or later FAA approved revisions pertain to this same subject. Amendment 39-1687 became effective August 18, 1973.

This Amendment 39-1712 becomes effective September 14, 1973.

## 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/73-15-02/models.md
Every aircraft: https://openairdocs.org/ad/73-15-02/aircraft.md

Its text cites no advisory circulars or STCs.

---
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.