AD 47-35-01

final rule

Airworthiness Directives; Sikorsky Model R44-B Helicopter

AD Number
47-35-01
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Holmes, Douglas W. R-4B (Army) Airworthiness Directives; Sikorsky Model R44-B Helicopter

Unsafe Condition

Failure of the main rotor links due to lack of lubrication causing loss of flight control.

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

Required Actions

Re-work main rotor links (P/N VS 36181) by removing and inspecting for cracks, machining oil grooves, replacing bearings with P/N AT-16-OH if original bearings are P/N AT-16, and following specified cleaning and inspection methods.

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

Compliance Time

before November 15, 1947

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

Affected Aircraft

Sikorsky Model R4-B Helicopter Serial Numbers 43-46500 to 43-46502 and 43-46504 to 43-46539 Inclusive.

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

Federal Register Abstract

Main Rotor Links Rework

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_47-35-01.html
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AD Number:
47-35-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Sikorsky Model R44-B Helicopter
Subject:
Main Rotor Links Rework
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Holmes, Douglas W.
Model:
R-4B (Army)
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Superseded AD: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Superseded By: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: 47-35-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   47-35-01

SUBJECT HEADING:   Airworthiness Directives; Sikorsky Model R44-B Helicopter

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   47-35-01 SIKORSKY: (Was Mandatory Note 1 of AD-7L-1.) Applies to Model R4-B Helicopter Serial Numbers 43-46500 to 43-46502 and 43-46504 to 43-46539 Inclusive.

Compliance required before November 15, 1947.

To reduce the possibility of loss of flight control due to failure of the main rotor links from lack of lubrication, the links should be reworked in accordance with the following instructions. This change involves the removal and inspection of main rotor link, P/N VS 36181 and machining of oil grooves.

1. Strip paint from the subject links with a paint remover or lacquer thinner, Specification No. AN-TT-T-256 or equivalent. Do not use scraper or wire brush on links, because small cracks may be filled in and covered.

2. Visually inspect main rotor links, P/N VS 36181 by one of the following methods for cracks around link pin hole and longitudinally along what was the flash line in original forging. (See Figure 1.) If cracks are present, links should be scrapped.


AD 47-35-01

(a) Visual inspection after re-anodizing; or

(b) By caustic etching; or

(c) By an approved fluorescent-black light method.

3. Machine oil grooves. (See Figure 1.)

4. Remove burrs and clean after machining.

5. Inspect the two bearings removed from each of the three subject links.

(a) If bearings removed are P/N AT-16, replace with P/N AT-16-OH bearings on assembly. (Bearing AT-16-OH is an AT-16 bearing with an oil hole added to its outer race.)

(b) If bearings removed are P/N AT-16-OH and retainer washers are damaged or show evidence of foreign matter, they are to be replaced.

(Sikorsky Service Bulletin R-4B No. 10 and Army T. O. 01-230HA-15 also cover this same subject.)

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_47-35-01.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
47-35-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Sikorsky Model R44-B Helicopter
Subject:
Main Rotor Links Rework
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Holmes, Douglas W.
Model:
R-4B (Army)
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: 47-35-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   47-35-01

SUBJECT HEADING:   Airworthiness Directives; Sikorsky Model R44-B Helicopter

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   47-35-01 SIKORSKY: (Was Mandatory Note 1 of AD-7L-1.) Applies to Model R4-B Helicopter Serial Numbers 43-46500 to 43-46502 and 43-46504 to 43-46539 Inclusive.

Compliance required before November 15, 1947.

To reduce the possibility of loss of flight control due to failure of the main rotor links from lack of lubrication, the links should be reworked in accordance with the following instructions. This change involves the removal and inspection of main rotor link, P/N VS 36181 and machining of oil grooves.

1. Strip paint from the subject links with a paint remover or lacquer thinner, Specification No. AN-TT-T-256 or equivalent. Do not use scraper or wire brush on links, because small cracks may be filled in and covered.

2. Visually inspect main rotor links, P/N VS 36181 by one of the following methods for cracks around link pin hole and longitudinally along what was the flash line in original forging. (See Figure 1.) If cracks are present, links should be scrapped.


AD 47-35-01

(a) Visual inspection after re-anodizing; or

(b) By caustic etching; or

(c) By an approved fluorescent-black light method.

3. Machine oil grooves. (See Figure 1.)

4. Remove burrs and clean after machining.

5. Inspect the two bearings removed from each of the three subject links.

(a) If bearings removed are P/N AT-16, replace with P/N AT-16-OH bearings on assembly. (Bearing AT-16-OH is an AT-16 bearing with an oil hole added to its outer race.)

(b) If bearings removed are P/N AT-16-OH and retainer washers are damaged or show evidence of foreign matter, they are to be replaced.

(Sikorsky Service Bulletin R-4B No. 10 and Army T. O. 01-230HA-15 also cover this same subject.)

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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