AD 47-47-05

final rule

Martin Model 202 Aircraft

AD Number
47-47-05
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.
Technical illustration of an aircraft turbine engine assembly
Problem area Engine

Applicability

TypeManufacturerModelDetails
aircraft Martin-Marietta Corporation 202 Martin Model 202 Aircraft

Unsafe Condition

Cracks at combustion chamber and heat exchanger end plates on Stewart-Warner 921-B heaters in cabin and wing systems may lead to heater failure.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Inspect combustion chamber and heat exchanger end plates for cracks at specified intervals. Replace heaters showing impending failure. Conduct complete inspections and pressure tests every 300/600 hours (cabin/wing) and repeat at shorter intervals post-initial inspection.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Inspections must be conducted before further flight as per the specified intervals: cabin heaters at each 30 hours, wing heaters at each 60 hours. Complete inspections every 300/600 hours (cabin/wing), then every 100/200 hours thereafter.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Martin-Marietta Corporation Model 202 Aircraft with Stewart-Warner 921-B heaters in cabin and wing systems.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

Stewart-Warner 921B Heaters

Applicability Source Text

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AD Final Rules - DRS_47-47-05.html
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AD Number:
47-47-05
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Martin Model 202 Aircraft
Subject:
Stewart-Warner 921B Heaters
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Martin-Marietta Corporation
Model:
202
Product Type:
Aircraft
Product Subtype:
Large 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Superseded AD: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Superseded By: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: 47-47-05
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   47-47-05

SUBJECT HEADING:   Martin Model 202 Aircraft

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
47-47-05 MARTIN: (Was Service Note 1 of AD-795-1.) Applies to Model 202 Aircraft.

The Stewart-Warner 921-B heaters in the Cabin heating and wing thermal deicing systems shall be inspected in accordance with the following: Any heaters indicating impending failure as a result of these inspections shall be replaced immediately:

1. Inspect combustion chamber and heat exchanger end plates on each end of the cabin heaters for signs of cracks at each 30 hours of airplane operation. For wing heaters this inspection should be conducted at each 60 hours of airplane operation.

2. Remove cabin heater for complete inspection and pressure test every 300 hours of airplane operation. In the case of wing heaters this inspection should be conducted at not less than every 600 hours of airplane operation.

3. Item 2. is to be repeated every 100 hours of airplane operation after the first 300- hour inspection for cabin heaters and every 200 hours of operation after the first 600-hour inspection in the case of wing heaters.

NOTE: The above inspection periods may be varied within reasonable limits to suit the normal inspection periods of scheduled air carrier operators at the discretion of the assigned CAA Maintenance Inspector. If heater operating time is logged separately from airplane operating time, the inspections specified in 2. and 3. may be conducted on the basis of heater operating time except that, if this is done, both wing and cabin heaters should be inspected after the first 300 hours and each 100 hours thereafter.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_47-47-05.html
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 Feedback
Details
AD Number:
47-47-05
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Martin Model 202 Aircraft
Subject:
Stewart-Warner 921B Heaters
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Martin-Marietta Corporation
Model:
202
Product Type:
Aircraft
Product Subtype:
Large 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: 47-47-05
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   47-47-05

SUBJECT HEADING:   Martin Model 202 Aircraft

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
47-47-05 MARTIN: (Was Service Note 1 of AD-795-1.) Applies to Model 202 Aircraft.

The Stewart-Warner 921-B heaters in the Cabin heating and wing thermal deicing systems shall be inspected in accordance with the following: Any heaters indicating impending failure as a result of these inspections shall be replaced immediately:

1. Inspect combustion chamber and heat exchanger end plates on each end of the cabin heaters for signs of cracks at each 30 hours of airplane operation. For wing heaters this inspection should be conducted at each 60 hours of airplane operation.

2. Remove cabin heater for complete inspection and pressure test every 300 hours of airplane operation. In the case of wing heaters this inspection should be conducted at not less than every 600 hours of airplane operation.

3. Item 2. is to be repeated every 100 hours of airplane operation after the first 300- hour inspection for cabin heaters and every 200 hours of operation after the first 600-hour inspection in the case of wing heaters.

NOTE: The above inspection periods may be varied within reasonable limits to suit the normal inspection periods of scheduled air carrier operators at the discretion of the assigned CAA Maintenance Inspector. If heater operating time is logged separately from airplane operating time, the inspections specified in 2. and 3. may be conducted on the basis of heater operating time except that, if this is done, both wing and cabin heaters should be inspected after the first 300 hours and each 100 hours thereafter.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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