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)
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Crankcase Vent Line Ice
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_72-03-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-03-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; CESSNA Model 421B Airplanes Subject: Crankcase Vent Line Ice Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 02/04/1972 Make: Cessna Aircraft Company Model: 421B Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 72-03-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1388 AD NUMBER: 72-03-04 SUBJECT HEADING: Airworthiness Directives; CESSNA Model 421B Airplanes ACTION: SUMMARY: DATES: Effective February 4, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-03-04 CESSNA: Amdt. 39-1388. Applies to Model 421B (S/Ns 421B0001 through 421B0149) airplanes. Compliance: Within the next 50 hours' time in service after the effective date of this AD, unless already accomplished. To prevent blockage of the crankcase vent line by ice with subsequent engine failure due to loss of engine oil, accomplish the following modifications in accordance with Cessna Service Letter ME72-2, dated January 28, 1972, or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region: A) Install a protective insulation sleeve over the crankcase vent line and scarf the vent line outlet to face aft. B) Install propeller shaft seal retainer on each engine. This amendment becomes effective February 4, 1972. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_72-03-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-03-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; CESSNA Model 421B Airplanes Subject: Crankcase Vent Line Ice Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 02/04/1972 Make: Cessna Aircraft Company Model: 421B Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 72-03-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1388 AD NUMBER: 72-03-04 SUBJECT HEADING: Airworthiness Directives; CESSNA Model 421B Airplanes ACTION: SUMMARY: DATES: Effective February 4, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-03-04 CESSNA: Amdt. 39-1388. Applies to Model 421B (S/Ns 421B0001 through 421B0149) airplanes. Compliance: Within the next 50 hours' time in service after the effective date of this AD, unless already accomplished. To prevent blockage of the crankcase vent line by ice with subsequent engine failure due to loss of engine oil, accomplish the following modifications in accordance with Cessna Service Letter ME72-2, dated January 28, 1972, or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region: A) Install a protective insulation sleeve over the crankcase vent line and scarf the vent line outlet to face aft. B) Install propeller shaft seal retainer on each engine. This amendment becomes effective February 4, 1972. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
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