AD 56-08-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Curtiss-Wright Corporation | C632S | CURTISS Models C632S, C634D and C634S Propellers |
| aircraft | Curtiss-Wright Corporation | C634D | CURTISS Models C632S, C634D and C634S Propellers |
| aircraft | Curtiss-Wright Corporation | C634S | CURTISS Models C632S, C634D and C634S Propellers |
| propeller | Curtiss-Wright Corporation | C632S | CURTISS Models C632S, C634D and C634S Propellers |
| propeller | Curtiss-Wright Corporation | C634D | CURTISS Models C632S, C634D and C634S Propellers |
| propeller | Curtiss-Wright Corporation | C634S | CURTISS Models C632S, C634D and C634S Propellers |
Unsafe Condition
Failure or malfunction of low pitch limit switches P/N 110425 and P/N 154592 beyond normal service wear could result in improper pitch control or loss of pitch limitation function.
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Required Actions
Replace low pitch limit switches P/N 110425 at intervals not exceeding specified flight hours per aircraft type. Disassemble and visually inspect low pitch limit switches P/N 154592 at the same intervals, checking for proper operation and mechanical/electrical condition; replace parts or assembly if adverse conditions are found.
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Compliance Time
Compliance required as indicated.
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Affected Aircraft
Curtiss-Wright Corporation Models C632S, C634D, and C634S Propellers installed on Douglas DC-6, Lockheed 749, Lockheed 1049, and Convair 240 Series Aircraft.
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Federal Register Abstract
Pitch Limit Switches
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_56-08-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 56-08-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: CURTISS Models C632S, C634D and C634S Propellers Subject: Pitch Limit Switches Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Curtiss-Wright Corporation Model: C632S | C634D | C634S Product Type: Propeller Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 56-08-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 56-08-01 SUBJECT HEADING: CURTISS Models C632S, C634D and C634S Propellers ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 56-08-01 CURTISS: Applies to All Models C632S, C634D and C634S Propellers. Compliance required as indicated. I. Replace low pitch limit switches P/N 110425 at not more than the following intervals: Douglas DC-6 Series Aircraft 3,500 Hours Lockheed 749 Series Aircraft 3,500 Hours Lockheed 1049 Series Aircraft 3,500 Hours Convair 240 Series Aircraft 1,000 Hours (Curtiss Service Bulletin No. 52 dated December 29, 1949, and appropriate service manuals also cover these recommendations.) II. Disassemble and visually inspect low pitch limit switches P/N 154592 at not more than the same intervals. Inspect for proper switch operation and for mechanical and electrical condition. Failure or malfunction other than normal service wear shall be cause for replacement of switch parts or of the assembly. Switches not revealing adverse conditions may be returned to service. This supersedes Section III of AD 53-05-01. FOOTER:
Document Text
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AD Final Rules - DRS_56-08-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 56-08-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: CURTISS Models C632S, C634D and C634S Propellers Subject: Pitch Limit Switches Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Curtiss-Wright Corporation Model: C632S | C634D | C634S Product Type: Propeller Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 56-08-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 56-08-01 SUBJECT HEADING: CURTISS Models C632S, C634D and C634S Propellers ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 56-08-01 CURTISS: Applies to All Models C632S, C634D and C634S Propellers. Compliance required as indicated. I. Replace low pitch limit switches P/N 110425 at not more than the following intervals: Douglas DC-6 Series Aircraft 3,500 Hours Lockheed 749 Series Aircraft 3,500 Hours Lockheed 1049 Series Aircraft 3,500 Hours Convair 240 Series Aircraft 1,000 Hours (Curtiss Service Bulletin No. 52 dated December 29, 1949, and appropriate service manuals also cover these recommendations.) II. Disassemble and visually inspect low pitch limit switches P/N 154592 at not more than the same intervals. Inspect for proper switch operation and for mechanical and electrical condition. Failure or malfunction other than normal service wear shall be cause for replacement of switch parts or of the assembly. Switches not revealing adverse conditions may be returned to service. This supersedes Section III of AD 53-05-01. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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