AD 72-03-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Cessna Aircraft Company | 421B | Airworthiness Directives; CESSNA Model 421B Airplanes |
Unsafe Condition
Blockage of the crankcase vent line by ice leading to engine failure due to loss of engine oil.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install a protective insulation sleeve over the crankcase vent line and scarf the vent line outlet to face aft. Install propeller shaft seal retainer on each engine.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 50 hours' time in service after the effective date of this AD
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Affected Aircraft
Cessna Model 421B (S/Ns 421B0001 through 421B0149)
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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