AD 57-12-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Scotts-Bell 47 Inc | 47B | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47B3 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47D | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47D1 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G-2 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47H-1 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47J | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
Unsafe Condition
Excessive play in the metal tail rotor blade and hub assembly and the pitch control mechanism can result in blade flutter.
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Required Actions
Inspect the metal tail rotor blade and hub assembly and pitch control mechanism as required in Part A of Bell Mandatory Service Bulletin No. 121SB. Inspect metal tail rotor blades P/N 47-642-102-5 for minimum 0.750 inch thickness at blade station 14.00; replace blades below this thickness.
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Compliance Time
as soon as possible but not later than August 1, 1957
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Affected Aircraft
Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J helicopters with metal tail rotor blades (Part A); Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, and 47H1 helicopters with metal tail rotor blades P/N 47-642-102-5 (Part B)
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Federal Register Abstract
Tail Rotor Blade Inspection
Applicability Source Text
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AD Final Rules - DRS_57-12-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 57-12-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters Subject: Tail Rotor Blade Inspection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Scotts-Bell 47 Inc Model: 47B | 47B3 | 47D | 47D1 | 47G | 47G-2 | 47H-1 | 47J 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: 57-12-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 57-12-04 SUBJECT HEADING: Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 57-12-04 BELL: Part A Below Applies to the Following Model 47 Helicopters Having Metal Tail Rotor Blades: 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J. Part B Below Applies to the Following 47 Helicopters Having Metal Tail Rotor Blades P/N 47-642-102-5; 47B, 47B3, 47D, 47D1, 47G, 47G2, and 47H1. Compliance required as soon as possible but not later than August 1, 1957. Part A. Due to the possibility of excessive play in the metal tail rotor blade and hub assembly and the pitch control mechanism which can result in blade flutter, the inspection as required in Part A of Bell Mandatory Service Bulletin No. 121SB, dated April 2, 1957, must be accomplished. Part B. Metal tail rotor blades, P/N 47-642-102-5 should be inspected for proper thickness at blade station 14.00. This thickness should be a minimum of 0.750 inch at the thickest part of the blade. Blades measuring less than 0.750 inch are required to be removed and replaced with acceptable blades. (Part B of Bell Mandatory Service Bulletin No. 121SB dated April 2, 1957, covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_57-12-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 57-12-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters Subject: Tail Rotor Blade Inspection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Scotts-Bell 47 Inc Model: 47B | 47B3 | 47D | 47D1 | 47G | 47G-2 | 47H-1 | 47J 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: 57-12-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 57-12-04 SUBJECT HEADING: Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 57-12-04 BELL: Part A Below Applies to the Following Model 47 Helicopters Having Metal Tail Rotor Blades: 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J. Part B Below Applies to the Following 47 Helicopters Having Metal Tail Rotor Blades P/N 47-642-102-5; 47B, 47B3, 47D, 47D1, 47G, 47G2, and 47H1. Compliance required as soon as possible but not later than August 1, 1957. Part A. Due to the possibility of excessive play in the metal tail rotor blade and hub assembly and the pitch control mechanism which can result in blade flutter, the inspection as required in Part A of Bell Mandatory Service Bulletin No. 121SB, dated April 2, 1957, must be accomplished. Part B. Metal tail rotor blades, P/N 47-642-102-5 should be inspected for proper thickness at blade station 14.00. This thickness should be a minimum of 0.750 inch at the thickest part of the blade. Blades measuring less than 0.750 inch are required to be removed and replaced with acceptable blades. (Part B of Bell Mandatory Service Bulletin No. 121SB dated April 2, 1957, covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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