AD 57-07-02

final rule

Airworthiness Directives; Bell Model 47 Helicopters

AD Number
57-07-02
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.
Technical illustration of a helicopter rotor hub assembly
Problem area Rotor system

Applicability

TypeManufacturerModelDetails
aircraft Scotts-Bell 47 Inc 47 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47B Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47B3 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47D Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47D1 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47E Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-2 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-2A Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-2A-1 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-3 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-3B Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-3B-1 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-3B-2 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-3B-2A Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-4 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-4A Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-5 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47G-5A Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47H-1 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47J Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47J-2 Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47J-2A Airworthiness Directives; Bell Model 47 Helicopters
aircraft Scotts-Bell 47 Inc 47K Airworthiness Directives; Bell Model 47 Helicopters

Unsafe Condition

The rotor hub equalizer link assembly, P/N 47-120-025-1, may have insufficient threads engaged due to improper assembly, leading to potential failure of the main rotor hub system.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Inspect rod ends P/N 47-120-025-7 and P/N 47-120-025-5 for adequate distance between shank ends. If dimensions exceed limits, remove link assembly, drill a new inspection hole, reassemble, and rerig the hub assembly. Compliance required by April 15, 1957, or during next main rotor hub overhaul.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

by April 15, 1957, unless item 2 has been accomplished. Rework on, or before, next overhaul of main rotor hub assembly.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Scotts-Bell 47 Inc Model 47 Helicopters except serial numbers: Model 47G 1529, 1689 and Up; 47G2 1506, 1957 and Up; Model 47H1 1361, 1534 and Up; Model 47J 1420, 1421, 1423, 1424, 1428 and Up; Model 47K.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

Rotor Hub Equalizer Link

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_57-07-02.html
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AD Number:
57-07-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Bell Model 47 Helicopters
Subject:
Rotor Hub Equalizer Link
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Scotts-Bell 47 Inc
Model:
47 | 47B | 47B3 | 47D | 47D1 | 47E | 47G | 47G-2 | 47G-2A | 47G-2A-1 | 47G-3 | 47G-3B | 47G-3B-1 | 4...Show more
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: 57-07-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   57-07-02

SUBJECT HEADING:   Airworthiness Directives; Bell Model 47 Helicopters

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
57-07-02 BELL: Applies to Model 47 Helicopters Except the Following: Model 47G 1529, 1689 and Up; 47G2 1506, 1957 and Up; Model 47H1 1361, 1534 and Up; Model 47J 1420, 1421, 1423, 1424, 1428 and Up; Model 47K.

Compliance required as indicated.

1. In order to insure that rotor hub equalizer link assembly, P/N 47-120-025-1, is assembled with sufficient threads engaged to meet safety requirements, the following inspection must be conducted and part reworked as necessary by April 15, 1957, unless item 2 has been accomplished.

(a) Inspect rod end, P/N 47-120-025-7, for adequate distance between end of shank to safety inspection hole, 0.230 to 0.270 inch required.

(b) Inspect for adequate distance between shank end of P/N 47-120-025-5 rod end shank end of P/N 47-120-025-7 rod end. Maximum of 15/32 (0.468) inch is allowed. NOTE: If dimension between rod ends exceeds 15/32 (0.468) inch, hub assembly must be rerigged and link assemblies must be adjusted until this dimension is below this valve.

2. Rework on, or before, next overhaul of main rotor hub assembly. Rework link assemblies, P/N 47-120-025-1, which do not meet conditions described in above inspection, item 1(a) as follows:

(a) Remove link assembly, P/N 47-120-025-1 from main rotor hub assembly and remove rod end, P/N 47-120-025-7 from link assembly.

(b) Drill a No. 50 (0.070) inch diameter hole through shank at a point 0.230- 0.270 inch from shank end and 90 degrees from existing inspection hole.

(c) Reassemble link assembly, install on hub assembly, and rerig hub assembly. Use new safety inspection hole to determine that rod end has sufficient threads engaged.

(Bell Service Bulletin No. 118SB dated February 1, 1957, covers this same subject.)

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_57-07-02.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
57-07-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Bell Model 47 Helicopters
Subject:
Rotor Hub Equalizer Link
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Scotts-Bell 47 Inc
Model:
47 | 47B | 47B3 | 47D | 47D1 | 47E | 47G | 47G-2 | 47G-2A | 47G-2A-1 | 47G-3 | 47G-3B | 47G-3B-1 | 4...Show more
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: 57-07-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   57-07-02

SUBJECT HEADING:   Airworthiness Directives; Bell Model 47 Helicopters

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
57-07-02 BELL: Applies to Model 47 Helicopters Except the Following: Model 47G 1529, 1689 and Up; 47G2 1506, 1957 and Up; Model 47H1 1361, 1534 and Up; Model 47J 1420, 1421, 1423, 1424, 1428 and Up; Model 47K.

Compliance required as indicated.

1. In order to insure that rotor hub equalizer link assembly, P/N 47-120-025-1, is assembled with sufficient threads engaged to meet safety requirements, the following inspection must be conducted and part reworked as necessary by April 15, 1957, unless item 2 has been accomplished.

(a) Inspect rod end, P/N 47-120-025-7, for adequate distance between end of shank to safety inspection hole, 0.230 to 0.270 inch required.

(b) Inspect for adequate distance between shank end of P/N 47-120-025-5 rod end shank end of P/N 47-120-025-7 rod end. Maximum of 15/32 (0.468) inch is allowed. NOTE: If dimension between rod ends exceeds 15/32 (0.468) inch, hub assembly must be rerigged and link assemblies must be adjusted until this dimension is below this valve.

2. Rework on, or before, next overhaul of main rotor hub assembly. Rework link assemblies, P/N 47-120-025-1, which do not meet conditions described in above inspection, item 1(a) as follows:

(a) Remove link assembly, P/N 47-120-025-1 from main rotor hub assembly and remove rod end, P/N 47-120-025-7 from link assembly.

(b) Drill a No. 50 (0.070) inch diameter hole through shank at a point 0.230- 0.270 inch from shank end and 90 degrees from existing inspection hole.

(c) Reassemble link assembly, install on hub assembly, and rerig hub assembly. Use new safety inspection hole to determine that rod end has sufficient threads engaged.

(Bell Service Bulletin No. 118SB dated February 1, 1957, covers this same subject.)

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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