- Effective
- August 15, 1973
- Models
- JT9D-20, JT9D-20J, JT9D-3A, JT9D-59A, JT9D-7, JT9D-70A and 14 more
- Registered aircraft
- 24 matched by model
- Product
- Engine
- Amendment
- 39-1698
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed May 30, 2024.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
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|---|---|---|---|
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On this page
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 TCDS · 2
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 24
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1969 | 1 |
|---|---|
| 1970 | 2 |
| 1971 | 1 |
| 1975 | 2 |
| 1979 | 1 |
| 1980 | 1 |
| 1982 | 2 |
| 1983 | 4 |
| 1984 | 1 |
| 1985 | 2 |
| 1986 | 1 |
| 1987 | 1 |
| 1988 | 1 |
| 1990 | 1 |
3 with no year recorded