# AD 57-08-07: Impeller Drive Gear Assemblies

- Type: Airworthiness directive
- Status: Current
- Products: Curtiss-Wright/Marquette Double Row Turbo Cyclone 972TC18DA1 (R-3350-34, -91), Double Row Turbo Cyclone 972TC18DA2, Double Row Turbo Cyclone 972TC18DA3, Double Row Turbo Cyclone 972TC18DA4, Double Row Turbo Cyclone 981TC18EA1, Double Row Turbo Cyclone 988TC18EA1, Double Row Turbo Cyclone 988TC18EA2, Double Row Turbo Cyclone 988TC18EA3, Double Row Turbo Cyclone 988TC18EA4, Double Row Turbo Cyclone 988TC18EA5 and Double Row Turbo Cyclone 988TC18EA6
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/35EC2E7D52E6F3028625685F0057D602.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/57-08-07

## The airworthiness directive

57-08-07 WRIGHT: Applies to All TC18DA and TC18EA Series Engines.

Compliance required at overhauls accomplished after May 1, 1957.

To improve the durability of the impeller drive gear assemblies of the subject engines, impeller drive secondary pinion bushings P/N's 170217, 170148, 145213 and 171190 are not eligible for use in engines overhauled after May 1, 1957.

This supersedes AD 57-01-03.

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E-287](https://openairdocs.org/tcds/E-287): Curtiss-Wright/Marquette Inc.; names 7 of 7 models: Double Row Turbo Cyclone 988TC18EA3, Double Row Turbo Cyclone 988TC18EA1, Double Row Turbo Cyclone 988TC18EA5, Double Row Turbo Cyclone 988TC18EA6, Double Row Turbo Cyclone 988TC18EA2, Double Row Turbo Cyclone 988TC18EA4, Double Row Turbo Cyclone 981TC18EA1
- [TCDS E-272](https://openairdocs.org/tcds/E-272): Curtiss-Wright/Marquette Inc.; names 4 of 4 models: Double Row Turbo Cyclone 972TC18DA4, Double Row Turbo Cyclone 972TC18DA3, Double Row Turbo Cyclone 972TC18DA1 (R-3350-34; -91), Double Row Turbo Cyclone 972TC18DA2

## 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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