AD 47-41-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Scotts-Bell 47 Inc | 47B | Airworthiness Directives; Bell Model 47B and 47B3 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47B3 | Airworthiness Directives; Bell Model 47B and 47B3 Helicopters |
Unsafe Condition
Failure of the inner race bearing attachment on the bottom of the main rotor mast could result in chipping and subsequent loss of main rotor mast integrity.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Incorporate a bolted retaining washer on the lower mast plug to improve attachment of the inner race bearing and prevent chipping.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
next 50-hour transmission teardown inspection after December 1, 1947
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Scotts-Bell 47 Inc Model 47B and 47B3 Helicopters
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Main Rotor Mast Plug
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_47-41-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-41-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Bell Model 47B and 47B3 Helicopters Subject: Main Rotor Mast Plug Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Scotts-Bell 47 Inc Model: 47B | 47B3 Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-41-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-41-04 SUBJECT HEADING: Airworthiness Directives; Bell Model 47B and 47B3 Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-41-04 BELL: (Was Mandatory Note 16 of AD-1H-2.) Applies to Models 47B and 47B3 Helicopters. Compliance required not later than next 50-hour transmission teardown inspection after December 1, 1947. To improve attachment of the inner race bearing on the bottom of the main rotor mast and to prevent possible chipping, the lower mast plug should incorporate a bolted retaining washer. (Bell Service Bulletin 47C41 dated June 26, 1947, covers the detail installation.) FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_47-41-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-41-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Bell Model 47B and 47B3 Helicopters Subject: Main Rotor Mast Plug Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Scotts-Bell 47 Inc Model: 47B | 47B3 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: 47-41-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-41-04 SUBJECT HEADING: Airworthiness Directives; Bell Model 47B and 47B3 Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-41-04 BELL: (Was Mandatory Note 16 of AD-1H-2.) Applies to Models 47B and 47B3 Helicopters. Compliance required not later than next 50-hour transmission teardown inspection after December 1, 1947. To improve attachment of the inner race bearing on the bottom of the main rotor mast and to prevent possible chipping, the lower mast plug should incorporate a bolted retaining washer. (Bell Service Bulletin 47C41 dated June 26, 1947, covers the detail installation.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2023-11-07
final ruleAirworthiness Directives; Various Helicopters
Unsafe Condition: unsafe condition on these products.
2009-12-01
final ruleAirworthiness Directives; Bell Helicopter Textron, Inc. Model 47, 47B, 47B3, 47D, 47D1, 47E, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K Helicopters
Unsafe Condition: An incorrectly installed main rotor blade box beam clip (clip) could result in a main rotor blade spar crack, loss of a main rotor blade, and subsequent loss of control of the helicopter.
98-07-09
final ruleAirworthiness Directives; Bell Helicopter Textron, Inc. Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K Helicopters
Unsafe Condition: Failure of the stabilizer bar damper link assembly due to separation of the damper link if the damper link rod end bushing loosens and exits the damper link rod end.
96-06-12
final ruleAirworthiness Directives; Bell Helicopter Textron, Inc. Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47-K Helicopters
Unsafe Condition: Inspect Tail Rotor Blade & Abrasion Strip