AD 55-25-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Scotts-Bell 47 Inc | 47G | Airworthiness Directives; Bell Model 47G Helicopters |
Unsafe Condition
The lateral cyclic bellcrank attachment bolt P/N AN 174-34 is too short, positioning the threaded area in the forward lateral bellcrank support bracket hole, which may result in the threads flattening out and elongating the support bracket bolt hole.
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Required Actions
Inspect the bellcrank support bracket bolt holes for elongation. Replace the AN 174-34 bolt with a longer bolt P/N AN 174-35 unless doubler plates are added, in which case install AN 174-36 bolts. If holes are elongated beyond 0.2520 inch diameter, add doubler plates and redrill and line ream new holes.
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Compliance Time
as soon as practical but not later than January 15, 1956
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Affected Aircraft
Bell Model 47G Helicopters Below Serial Number 1450 Which Have Hydraulic Boost System Installed
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Federal Register Abstract
Bellcrank Attachment Bolt
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_55-25-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 55-25-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Bell Model 47G Helicopters Subject: Bellcrank Attachment Bolt Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Scotts-Bell 47 Inc Model: 47G Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 55-25-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 55-25-01 SUBJECT HEADING: Airworthiness Directives; Bell Model 47G Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 55-25-01 BELL: Applies to Model 47G Helicopters Below Serial Number 1450 Which Have Hydraulic Boost System Installed. Compliance required as soon as practical but not later than January 15, 1956. The manufacturer advises that the lateral cyclic bellcrank, P/N 47-725-073-1 attachment bolt P/N AN 174-34 is too short, positioning the threaded area in the forward lateral bellcrank support bracket hole, which may result in the threads flattening out and elongating the support bracket bolt hole. It is therefore requested that the bolt holes in the bellcrank support bracket be inspected for elongation and the bolt replaced with a longer bolt. If the bolt holes are found elongated beyond permissible tolerance (maximum hole diameter of 0.2520 inch) doubler plates must be added. Redrill and line ream new holes. Replace the AN 174-34 bolt with a new longer bolt P/N AN 174-35, unless doubler plates are added, in which case install AN 174-36 bolts. (Bell's Mandatory Service Bulletin No. 104, dated November 11, 1955, covers this same subject.) FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_55-25-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 55-25-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Bell Model 47G Helicopters Subject: Bellcrank Attachment Bolt Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Scotts-Bell 47 Inc Model: 47G 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: AIRWORTHINESS DIRECTIVES FINAL RULES: 55-25-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 55-25-01 SUBJECT HEADING: Airworthiness Directives; Bell Model 47G Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 55-25-01 BELL: Applies to Model 47G Helicopters Below Serial Number 1450 Which Have Hydraulic Boost System Installed. Compliance required as soon as practical but not later than January 15, 1956. The manufacturer advises that the lateral cyclic bellcrank, P/N 47-725-073-1 attachment bolt P/N AN 174-34 is too short, positioning the threaded area in the forward lateral bellcrank support bracket hole, which may result in the threads flattening out and elongating the support bracket bolt hole. It is therefore requested that the bolt holes in the bellcrank support bracket be inspected for elongation and the bolt replaced with a longer bolt. If the bolt holes are found elongated beyond permissible tolerance (maximum hole diameter of 0.2520 inch) doubler plates must be added. Redrill and line ream new holes. Replace the AN 174-34 bolt with a new longer bolt P/N AN 174-35, unless doubler plates are added, in which case install AN 174-36 bolts. (Bell's Mandatory Service Bulletin No. 104, dated November 11, 1955, covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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