AD 58-02-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | UH-12 | Airworthiness Directives; Hiller Model UH-12 Series Helicopters |
| aircraft | Hiller Aviation | UH-12A | Airworthiness Directives; Hiller Model UH-12 Series Helicopters |
| aircraft | Hiller Aviation | UH-12B | Airworthiness Directives; Hiller Model UH-12 Series Helicopters |
| aircraft | Hiller Aviation | UH-12C | Airworthiness Directives; Hiller Model UH-12 Series Helicopters |
| aircraft | Hiller Aviation | UH-12D | Airworthiness Directives; Hiller Model UH-12 Series Helicopters |
Unsafe Condition
With a Marvel-Schebler Model MA-4-5AA carburetor installed, it is possible to start and run the engine with the carburetor mixture control in the idle cutoff position if the throttle is partially or fully opened. However, as soon as the throttle is fully closed, the idle cutoff will operate and shut off the engine.
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Required Actions
Delete the carburetor mixture control from the cockpit and secure the carburetor setting at 'ALT.COMP' at the carburetor. An appropriate FAA approved Helicopter Flight Manual revision is required.
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Compliance Time
June 1, 1958
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Affected Aircraft
Hiller Model UH-12 Series Helicopters equipped with Marvel-Schebler Automatic Altitude Compensating Carburetor Model MA-4-5AA (Aircooled P/N 19588)
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Federal Register Abstract
Carburetor Mixture Control Removal
Applicability Source Text
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AD Final Rules - DRS_58-02-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 58-02-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Model UH-12 Series Helicopters Subject: Carburetor Mixture Control Removal Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation Model: UH-12 | UH-12A | UH-12B | UH-12C | UH-12D Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 58-02-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 58-02-03 SUBJECT HEADING: Airworthiness Directives; Hiller Model UH-12 Series Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 58-02-03 HILLER: Applies to UH-12 Series Helicopters Equipped With Marvel- Schebler Automatic Altitude Compensating Carburetor Model MA-4-5AA (Aircooled P/N 19588). Compliance required by June 1, 1958. With a Marvel-Schebler Model MA-4-5AA carburetor installed, it is possible to start and run the engine with the carburetor mixture control in the idle cutoff position if the throttle is partially or fully opened. However, as soon as the throttle is fully closed, the idle cutoff will operate and shut off the engine. Therefore, it would be possible to start the engine, take off, and fly with the mixture in idle cutoff, as long as the throttle is never closed. The first time the throttle is closed, however, as in autorotation, an immediate engine stoppage would occur. To prevent inadvertent engine stoppage in flight due to failure to place the carburetor mixture control in the "ALT.COMP" position before takeoff, the following measure is necessary: Delete the carburetor mixture control from the cockpit and secure the carburetor setting at "ALT.COMP" at the carburetor. Hiller will issue a service bulletin covering this subject. Appropriate FAA approved Helicopter Flight Manual revision required. FOOTER:
Document Text
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AD Final Rules - DRS_58-02-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 58-02-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Model UH-12 Series Helicopters Subject: Carburetor Mixture Control Removal Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation Model: UH-12 | UH-12A | UH-12B | UH-12C | UH-12D Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 58-02-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 58-02-03 SUBJECT HEADING: Airworthiness Directives; Hiller Model UH-12 Series Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 58-02-03 HILLER: Applies to UH-12 Series Helicopters Equipped With Marvel- Schebler Automatic Altitude Compensating Carburetor Model MA-4-5AA (Aircooled P/N 19588). Compliance required by June 1, 1958. With a Marvel-Schebler Model MA-4-5AA carburetor installed, it is possible to start and run the engine with the carburetor mixture control in the idle cutoff position if the throttle is partially or fully opened. However, as soon as the throttle is fully closed, the idle cutoff will operate and shut off the engine. Therefore, it would be possible to start the engine, take off, and fly with the mixture in idle cutoff, as long as the throttle is never closed. The first time the throttle is closed, however, as in autorotation, an immediate engine stoppage would occur. To prevent inadvertent engine stoppage in flight due to failure to place the carburetor mixture control in the "ALT.COMP" position before takeoff, the following measure is necessary: Delete the carburetor mixture control from the cockpit and secure the carburetor setting at "ALT.COMP" at the carburetor. Hiller will issue a service bulletin covering this subject. Appropriate FAA approved Helicopter Flight Manual revision required. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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