AD 52-04-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Martin-Marietta Corporation | 202 | MARTIN Models 202 and 202A Aircraft |
| aircraft | Martin-Marietta Corporation | 202A | MARTIN Models 202 and 202A Aircraft |
Unsafe Condition
The heater control system's shared controls and wiring between two wing anti-icing heaters could lead to unintended activation or failure of both heaters, compromising engine ignition and fuel systems.
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Required Actions
Modify the system so each control serves only one heater, including modifying the emergency high heat cutout switch, firewall shutoff switch, fuel pump circuit breaker, fuel shutoff relay, wiring to solenoid valves, fuel booster pump relay, ignition components (for 202 models), and AC safety relay (for 202).
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Compliance Time
not later than July 1, 1952
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Affected Aircraft
Martin-Marietta Corporation Models 202 and 202A Aircraft except as noted in the AD
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Federal Register Abstract
Heater Control Modification
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_52-04-07.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 52-04-07 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: MARTIN Models 202 and 202A Aircraft Subject: Heater Control Modification Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Martin-Marietta Corporation Model: 202 | 202A Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 52-04-07 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 52-04-07 SUBJECT HEADING: MARTIN Models 202 and 202A Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 52-04-07 MARTIN: Applies to All Models 202 and 202A Aircraft Except as Noted. Compliance required not later than July 1, 1952. The following controls and their wiring are common to two wing anti-icing heaters. The controls listed are identical in each nacelle. Modify the system so each of the controls serves only one heater: 1. Emergency high heat 400 degrees cutout switch. 2. Firewall shutoff switch. 3. Fuel pump circuit breaker (supplies power to ignition controls and master fuel controls). 4. Fuel shutoff relay. 5. Wiring to the master and auxiliary solenoid valves. 6. Fuel booster pump relay (has dual power input but single ground on the control circuit). 7. Ignition relay (202 only). 8. Ignition transformer (202 only). 9. Ignition circuit breaker (202 only). 10. AC safety relay (202 only). (Trans World Airlines Engineering Order 5838 covers this same subject for the 202A). FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_52-04-07.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 52-04-07 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: MARTIN Models 202 and 202A Aircraft Subject: Heater Control Modification Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Martin-Marietta Corporation Model: 202 | 202A 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: 52-04-07 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 52-04-07 SUBJECT HEADING: MARTIN Models 202 and 202A Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 52-04-07 MARTIN: Applies to All Models 202 and 202A Aircraft Except as Noted. Compliance required not later than July 1, 1952. The following controls and their wiring are common to two wing anti-icing heaters. The controls listed are identical in each nacelle. Modify the system so each of the controls serves only one heater: 1. Emergency high heat 400 degrees cutout switch. 2. Firewall shutoff switch. 3. Fuel pump circuit breaker (supplies power to ignition controls and master fuel controls). 4. Fuel shutoff relay. 5. Wiring to the master and auxiliary solenoid valves. 6. Fuel booster pump relay (has dual power input but single ground on the control circuit). 7. Ignition relay (202 only). 8. Ignition transformer (202 only). 9. Ignition circuit breaker (202 only). 10. AC safety relay (202 only). (Trans World Airlines Engineering Order 5838 covers this same subject for the 202A). FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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