AD 81-04-03

final rule

Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters

AD Number
81-04-03
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 Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. OH-13H Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. OH-13E Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47B Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47B3 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47D Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47D1 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47E Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-2 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-2A Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-2A-1 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-3 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-3B Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-3B-1 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-3B-2 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-3B-2A Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-4 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-4A Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-5 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47G-5A Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47H-1 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47J Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47J-2 Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47J-2A Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. 47K Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
aircraft Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Aviation, Inc. Fast Kat I (U.S. Army OH-13S) Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters

Unsafe Condition

Failure of the tail rotor drive assembly bearing could lead to possible loss of directional control.

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

Required Actions

Disassemble and inspect the tail rotor drive assembly to identify the bearing at the inboard end of the transmission tail rotor drive gear. If the bearing is not BHT P/N 47-620-929-001 or FAA-approved equivalent, replace it with BHT P/N 47-620-929-001 following BHT Alert Service Bulletin No. 47-80-6. Reassemble and reinstall as per maintenance manuals.

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

Compliance Time

within the next 600 hours' time in service after the effective date of this AD

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

Affected Aircraft

BELL Model 47 series and military OH-13 series helicopters with tail rotor drive quill assemblies P/N 47-620-631-3, P/N 47-620-631-35, P/N 47-620-541-3, P/N 47-620-541-7, or P/N 47-620-541-9, including those under Type Certificates H7SW, H5SW, and H2CE.

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

Federal Register Abstract

Tail Rotor Drive Assembly

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_81-04-03.html
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AD Number:
81-04-03
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
Subject:
Tail Rotor Drive Assembly
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
02/02/1981
Make:
Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Av...Show more
Model:
OH-13H | OH-13E | 47 | 47B | 47B3 | 47D | 47D1 | 47E | 47G | 47G-2 | 47G-2A | 47G-2A-1 | 47G-3 | 47G...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: 81-04-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-4029

AD NUMBER:   81-04-03

SUBJECT HEADING:   Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective February 2, 1981.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
81-04-03 BELL: Amendment 39-4029. Applies to Model 47 series helicopters and military Model OH-13 series helicopters certificated in all categories which utilize tail rotor drive quill assemblies, BHT P/N 47-620-631-3, P/N 47-620-631-35, P/N 47-620-541-3, P/N 47-620-541-7, or P/N 47-620-541-9. This also includes, but is not necessarily limited to, helicopters produced under the following Type Certificates:

H7SW - Texas Helicopter Corporation, U.S. Army OH-13/M74 series helicopter (BHT Model 47 series).

H5SW - Tomcat Helicopters, Inc., (Continental Copters, Inc.), U.S. Army OH-13H helicopter (BHT Model 47 series).

H2CE - Wilbur Isenburg (Hawkeye), U.S. Army OH-13E helicopter (BHT Model 47 series).

Compliance is required within the next 600 hours' time in service after the effective date of this AD, unless already accomplished.

To prevent the failure of the tail rotor drive assembly bearing and possible loss of directional control, accomplish the following:

(a) Disassemble and inspect the tail rotor drive assembly (BHT P/N 47-620-631-3, P/N 47-620-631-35, P/N 47-620-541-3, P/N 47-620-541-7, or P/N 47-620-541-9) as necessary to determine the identification of the bearing at the inboard end of the transmission tail rotor drive gear, P/N 47-620-568-1.

(b) If the bearing is BHT bearing P/N 47-620-929-001 or FAA-approved equivalent, reassemble and reinstall the tail rotor drive assembly as prescribed by the applicable maintenance and overhaul manuals.

(c) If the bearing identified in Item (a) is any part other than BHT P/N 47-620-929-001 or FAA-approved equivalent, replace the bearing with BHT bearing, P/N 47-620-929-001, in accordance with the instructions in BHT Alert Service Bulletin No. 47-80-6, "Replacement of Bearing, P/N 47-620-605-001, with Bearing, 47-620-929-001," dated May 15, 1980. Reassemble and reinstall the tail rotor drive assembly as prescribed by the applicable maintenance and overhaul manuals.

(d) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, Federal Aviation Administration.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part thereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Bell Helicopter Textron, Product Support Department, Post Office Box 482, Fort Worth, Texas 76101. These documents may also be examined at the Office of the Regional Counsel, Southwest Region, FAA, 4400 Blue Mound Road, Fort Worth, Texas, and at the FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD, which includes the incorporated material in full, is maintained by the FAA at their headquarters in Washington, D.C., and at the Southwest Regional Office in Fort Worth, Texas.

This amendment becomes effective February 2, 1981.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_81-04-03.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
81-04-03
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters
Subject:
Tail Rotor Drive Assembly
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
02/02/1981
Make:
Continental Copters, Inc. | Isenberg, Wilbur M. | McCreary, Gifton | Scotts-Bell 47 Inc | Teryjon Av...Show more
Model:
OH-13H | OH-13E | 47 | 47B | 47B3 | 47D | 47D1 | 47E | 47G | 47G-2 | 47G-2A | 47G-2A-1 | 47G-3 | 47G...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: 81-04-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-4029

AD NUMBER:   81-04-03

SUBJECT HEADING:   Airworthiness Directives; BELL Model 47 and Military OH-13 Series Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective February 2, 1981.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
81-04-03 BELL: Amendment 39-4029. Applies to Model 47 series helicopters and military Model OH-13 series helicopters certificated in all categories which utilize tail rotor drive quill assemblies, BHT P/N 47-620-631-3, P/N 47-620-631-35, P/N 47-620-541-3, P/N 47-620-541-7, or P/N 47-620-541-9. This also includes, but is not necessarily limited to, helicopters produced under the following Type Certificates:

H7SW - Texas Helicopter Corporation, U.S. Army OH-13/M74 series helicopter (BHT Model 47 series).

H5SW - Tomcat Helicopters, Inc., (Continental Copters, Inc.), U.S. Army OH-13H helicopter (BHT Model 47 series).

H2CE - Wilbur Isenburg (Hawkeye), U.S. Army OH-13E helicopter (BHT Model 47 series).

Compliance is required within the next 600 hours' time in service after the effective date of this AD, unless already accomplished.

To prevent the failure of the tail rotor drive assembly bearing and possible loss of directional control, accomplish the following:

(a) Disassemble and inspect the tail rotor drive assembly (BHT P/N 47-620-631-3, P/N 47-620-631-35, P/N 47-620-541-3, P/N 47-620-541-7, or P/N 47-620-541-9) as necessary to determine the identification of the bearing at the inboard end of the transmission tail rotor drive gear, P/N 47-620-568-1.

(b) If the bearing is BHT bearing P/N 47-620-929-001 or FAA-approved equivalent, reassemble and reinstall the tail rotor drive assembly as prescribed by the applicable maintenance and overhaul manuals.

(c) If the bearing identified in Item (a) is any part other than BHT P/N 47-620-929-001 or FAA-approved equivalent, replace the bearing with BHT bearing, P/N 47-620-929-001, in accordance with the instructions in BHT Alert Service Bulletin No. 47-80-6, "Replacement of Bearing, P/N 47-620-605-001, with Bearing, 47-620-929-001," dated May 15, 1980. Reassemble and reinstall the tail rotor drive assembly as prescribed by the applicable maintenance and overhaul manuals.

(d) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, Federal Aviation Administration.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part thereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Bell Helicopter Textron, Product Support Department, Post Office Box 482, Fort Worth, Texas 76101. These documents may also be examined at the Office of the Regional Counsel, Southwest Region, FAA, 4400 Blue Mound Road, Fort Worth, Texas, and at the FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD, which includes the incorporated material in full, is maintained by the FAA at their headquarters in Washington, D.C., and at the Southwest Regional Office in Fort Worth, Texas.

This amendment becomes effective February 2, 1981.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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