AD 54-25-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Cyclone 975C18CB1 | WRIGHT Models 975C18CB1, 972TC18DA1, and 972TC18DA2 Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 972TC18DA1 (R-3350-34, -91) | WRIGHT Models 975C18CB1, 972TC18DA1, and 972TC18DA2 Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 972TC18DA2 | WRIGHT Models 975C18CB1, 972TC18DA1, and 972TC18DA2 Engines |
Unsafe Condition
Front intermediate cam drive gear failures and associated possible engine overspeeding.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove specified intermediate cam drive gears (P/N's 138608, 138608 N, 171385, 171238, or 171387) from the front cam drive gear train. Use gears with increased tooth width and thick hubs (P/N's 171347, 171348, or 171994) in the front configuration. Follow assembly instructions in TC18DA Overhaul Manual sections V.17 and VIII.2, recording measurements on engine build-up sheets.
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Compliance Time
November 1, 1955 and at next and each subsequent overhaul.
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Affected Aircraft
Curtiss-Wright/Marquette, Inc. Models 975C18CB1, 972TC18DA1, and 972TC18DA2 engines.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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