AD 82-26-51 R1

final rule

Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 412 Helicopters

AD Number
82-26-51 R1
Status
final_rule
Effective Date
Product Category
aircraft
Docket
82-ASW-82
FR Citation
This information is not available.
Technical illustration of a helicopter rotor hub assembly
Problem area Rotor system

Applicability

TypeManufacturerModelDetails
aircraft Bell Helicopter Textron, Inc. 412 Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 412 Helicopters

Unsafe Condition

Failure of the main rotor yoke assemblies P/N 412-010-101-109, -113, -117, and -121 due to fatigue.

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

Required Actions

Reduce retirement life of yoke assemblies P/N 412-010-101-113, -117, and -121 to 700 hours time in service. Install flex indicator kit Bell P/N 412-703-006-101 within 25 hours time in service after AD effective date. Perform daily visual inspections of yoke assemblies and inspect flex indicators before first flight each day. Corrective action required if deflection is indicated per Bell Alert Service Bulletin 412-82-9 or approved equivalent.

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

Compliance Time

Effective December 2, 1983. Compliance required immediately for retirement life reduction; flex indicator installation within 25 hours time in service after effective date; daily inspections before first flight each day.

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

Affected Aircraft

Bell Helicopter Textron, Inc. Model 412 helicopters with main rotor yokes P/N 412-010-101-109, -113, -117, and -121.

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

Federal Register Abstract

Yoke Assemblies Service Time

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_82-26-51_R.html
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AD Number:
82-26-51 R1
Document Type:
AD Final Rules
Docket Number:
82-ASW-82
Subject Heading:
Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 412 Helicopters
Subject:
Yoke Assemblies Service Time
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
12/02/1983
Make:
Bell Helicopter Textron, Inc.
Model:
412
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: 82-26-51 R1
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   82-ASW-82

AMENDMENT:   39-4760

AD NUMBER:   82-26-51 R1

SUBJECT HEADING:   Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 412 Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective December 2, 1983.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
82-26-51 R1 BELL HELICOPTER TEXTRON, INC.: Amendment 39-4760. Applies to Bell Helicopter Textron, Inc., Model 412 helicopters certificated in all categories that are equipped with main rotor yokes P/N 412-010-101-109, -113, -117, and -121. (Airworthiness Docket No. 82-ASW-82.)

Compliance is required as indicated (unless already accomplished.)

To prevent failure of the main rotor yoke, accomplish the following:

(a) Effective immediately, the retirement life of yoke assemblies P/N 412-010-101- 113, -117, and -121 is reduced to 700 hours. Yokes with more than 675 hours time in service on the effective date of this AD may be operated an additional 25 hours maximum.

(b) Install flex indicator kit, Bell P/N 412-703-006-101, on yoke assemblies P/N 412-010-101-113, -117, and -121 within 25 hours time in service after the effective date of this AD. Before the first flight of each day perform an inspection of the flex indicators and perform corrective action when deflection is indicated in accordance with the instructions in Bell Alert Service Bulletin 412-82-9, dated 12/9/82, or an equivalent procedure approved by the Manager, Aircraft Certification Division, Federal Aviation Administration, Southwest Region.

(c) Before the first flight of each day perform a visual inspection of yoke assemblies P/N 412-010-101-109, -113, -117, and -121 in the area of the flexure concentrating on the area from the mast to the damper bridges including the transition radii from the flexure to the damper bridge mounting area, on both upper and lower surfaces of the yoke.

(d) In accordance with FAR 21.197, flight is permitted to a base where the requirements of this AD may be accomplished.

(e) Any equivalent means of compliance with this AD must be approved by the Manager, Aircraft Certification Division, Federal Aviation Administration, Southwest Region.

NOTE: Refer to Bell Helicopter Textron, Inc., Service Bulletin 412-82-9, dated 12/9/82, or FAA approved equivalent for flex indicator installation procedures.

This amendment becomes effective December 2, 1983, as to all persons except those persons to whom it was made immediately effective by telegraphic AD T82-26-51 issued December 8, 1982, which contained this amendment.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_82-26-51_R.html
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Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
82-26-51 R1
Document Type:
AD Final Rules
Docket Number:
82-ASW-82
Subject Heading:
Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 412 Helicopters
Subject:
Yoke Assemblies Service Time
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
12/02/1983
Make:
Bell Helicopter Textron, Inc.
Model:
412
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: 82-26-51 R1
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   82-ASW-82

AMENDMENT:   39-4760

AD NUMBER:   82-26-51 R1

SUBJECT HEADING:   Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 412 Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective December 2, 1983.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
82-26-51 R1 BELL HELICOPTER TEXTRON, INC.: Amendment 39-4760. Applies to Bell Helicopter Textron, Inc., Model 412 helicopters certificated in all categories that are equipped with main rotor yokes P/N 412-010-101-109, -113, -117, and -121. (Airworthiness Docket No. 82-ASW-82.)

Compliance is required as indicated (unless already accomplished.)

To prevent failure of the main rotor yoke, accomplish the following:

(a) Effective immediately, the retirement life of yoke assemblies P/N 412-010-101- 113, -117, and -121 is reduced to 700 hours. Yokes with more than 675 hours time in service on the effective date of this AD may be operated an additional 25 hours maximum.

(b) Install flex indicator kit, Bell P/N 412-703-006-101, on yoke assemblies P/N 412-010-101-113, -117, and -121 within 25 hours time in service after the effective date of this AD. Before the first flight of each day perform an inspection of the flex indicators and perform corrective action when deflection is indicated in accordance with the instructions in Bell Alert Service Bulletin 412-82-9, dated 12/9/82, or an equivalent procedure approved by the Manager, Aircraft Certification Division, Federal Aviation Administration, Southwest Region.

(c) Before the first flight of each day perform a visual inspection of yoke assemblies P/N 412-010-101-109, -113, -117, and -121 in the area of the flexure concentrating on the area from the mast to the damper bridges including the transition radii from the flexure to the damper bridge mounting area, on both upper and lower surfaces of the yoke.

(d) In accordance with FAR 21.197, flight is permitted to a base where the requirements of this AD may be accomplished.

(e) Any equivalent means of compliance with this AD must be approved by the Manager, Aircraft Certification Division, Federal Aviation Administration, Southwest Region.

NOTE: Refer to Bell Helicopter Textron, Inc., Service Bulletin 412-82-9, dated 12/9/82, or FAA approved equivalent for flex indicator installation procedures.

This amendment becomes effective December 2, 1983, as to all persons except those persons to whom it was made immediately effective by telegraphic AD T82-26-51 issued December 8, 1982, which contained this amendment.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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