AD 85-20-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Cessna Aircraft Company | 172RG | Airworthiness Directives; Cessna Model 172RG Airplanes |
Unsafe Condition
Carbon monoxide contamination entering the cabin area due to potential failure of the cabin heat system, including improper muffler core installation or damaged muffler core from drilling holes through the end plate or improper length attachment screws.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Deactivate the cabin heat system by removing the control cable and ensuring the valve spring mechanism functions or safety wiring the valve closed. Install a placard stating 'DO NOT USE CABIN HEAT' on the instrument panel. Inspect the muffler core for damage within 25 hours time-in-service after the AD's effective date and replace if damaged. Report defects within 10 days of inspection.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Prior to further flight for cabin heat deactivation and placard installation; within 25 hours time-in-service after the effective date for muffler inspection and replacement if needed.
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Affected Aircraft
Cessna Model 172RG (Serial Numbers 172RG1135 thru 172RG1187)
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Cabin Heat Deactivated
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_85-20-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 85-20-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Cessna Model 172RG Airplanes Subject: Cabin Heat Deactivated Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/05/1985 Make: Cessna Aircraft Company Model: 172RG Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 85-20-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5175 AD NUMBER: 85-20-01 SUBJECT HEADING: Airworthiness Directives; Cessna Model 172RG Airplanes ACTION: SUMMARY: DATES: Effective December 5, 1985. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 85-20-01 CESSNA: Amendment 39-5175. Applies to Model 172RG (Serial Numbers 172RG1135 thru 172RG1187) airplanes certificated in any category. Compliance: Required as indicated, unless already accomplished. To reduce the possibility of carbon monoxide contamination entering the cabin area, accomplish the following: (a) Prior to further flight: 1) Deactivate the cabin heat system by removing the cabin heat control cable from the control arm on the cabin heat valve located on the firewall at the right upper side of the engine compartment. Ensure that the valve spring mechanism is functioning and that the cabin heat valve is spring loaded to the closed position or safety wire the valve to the closed position. 2) Fabricate and install on the instrument panel visible to the pilot the following placard using letters of a minimum 0.10 inch in height: "DO NOT USE CABIN HEAT", and operate the airplane accordingly. (b) Within 25 hours time-in-service after the effective date of this AD, remove the muffler shroud and visually inspect the muffler core for damage as a result of drilling the holes through the end plate or improper length attachment screws and if damaged replace the muffler core prior to further flight. (c) The requirements of paragraph (a) of this AD are no longer required when paragraph (b) of this AD has been accomplished. (d) The airplane may be flown in accordance with FAR 21.197 to a location where this AD may be accomplished, providing cabin heat is not used during the flight. (e) An equivalent method of compliance may be used when approved by the Manager, Wichita Aircraft Certification Office, Federal Aviation Administration, Central Region, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209. (f) Report, in writing, all defects found to the Manager, Wichita Aircraft Certification Office, FAA, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209, within 10 days of the inspection required by paragraph (b) of this AD (Reporting approved by the Office of Management and Budget under OMB No. 2120-0056). This amendment became effective on December 5, 1985, to all persons except those to whom it has already been made effective by priority letter from the FAA dated September 27, 1985, and is identified as AD 85-20-01. FOOTER:
Document Text
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AD Final Rules - DRS_85-20-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 85-20-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Cessna Model 172RG Airplanes Subject: Cabin Heat Deactivated Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/05/1985 Make: Cessna Aircraft Company Model: 172RG 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: 85-20-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5175 AD NUMBER: 85-20-01 SUBJECT HEADING: Airworthiness Directives; Cessna Model 172RG Airplanes ACTION: SUMMARY: DATES: Effective December 5, 1985. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 85-20-01 CESSNA: Amendment 39-5175. Applies to Model 172RG (Serial Numbers 172RG1135 thru 172RG1187) airplanes certificated in any category. Compliance: Required as indicated, unless already accomplished. To reduce the possibility of carbon monoxide contamination entering the cabin area, accomplish the following: (a) Prior to further flight: 1) Deactivate the cabin heat system by removing the cabin heat control cable from the control arm on the cabin heat valve located on the firewall at the right upper side of the engine compartment. Ensure that the valve spring mechanism is functioning and that the cabin heat valve is spring loaded to the closed position or safety wire the valve to the closed position. 2) Fabricate and install on the instrument panel visible to the pilot the following placard using letters of a minimum 0.10 inch in height: "DO NOT USE CABIN HEAT", and operate the airplane accordingly. (b) Within 25 hours time-in-service after the effective date of this AD, remove the muffler shroud and visually inspect the muffler core for damage as a result of drilling the holes through the end plate or improper length attachment screws and if damaged replace the muffler core prior to further flight. (c) The requirements of paragraph (a) of this AD are no longer required when paragraph (b) of this AD has been accomplished. (d) The airplane may be flown in accordance with FAR 21.197 to a location where this AD may be accomplished, providing cabin heat is not used during the flight. (e) An equivalent method of compliance may be used when approved by the Manager, Wichita Aircraft Certification Office, Federal Aviation Administration, Central Region, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209. (f) Report, in writing, all defects found to the Manager, Wichita Aircraft Certification Office, FAA, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209, within 10 days of the inspection required by paragraph (b) of this AD (Reporting approved by the Office of Management and Budget under OMB No. 2120-0056). This amendment became effective on December 5, 1985, to all persons except those to whom it has already been made effective by priority letter from the FAA dated September 27, 1985, and is identified as AD 85-20-01. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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