AD 70-14-01

final rule

Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters

AD Number
70-14-01
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 47D1 Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters
aircraft Scotts-Bell 47 Inc 47G Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters
aircraft Scotts-Bell 47 Inc 47G-2 Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters
aircraft Scotts-Bell 47 Inc 47H-1 Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters

Unsafe Condition

Failure of tail rotor duplex pitch change bearing and improper installation of the duplex bearing and delta hinge bolts.

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

Required Actions

Inspect all duplex pitch change bearings within 50 hours time in service after the effective date. Replace bearings with 450+ hours time in service within 150 hours. Replace bearings with less than 450 hours before accumulating 600 hours. Use new P/N 47-641-131-1 and follow specified maintenance procedures.

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

Compliance Time

Compliance required as indicated in the AD: inspections and replacements must be done within specified time frames (50, 150, or 600 hours time in service) as per the bearing's time in service on the effective date.

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

Affected Aircraft

Bell Model 47D-1, 47G, 47G-2, and 47H-1 helicopters with duplex pitch change bearings P/N 47-641-131-1 or equipped with guide sleeves P/N 47-641-040 or 47-641-130.

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

Federal Register Abstract

Tail Rotor Pitch

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_70-14-01.html
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AD Number:
70-14-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters
Subject:
Tail Rotor Pitch
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/17/1970
Make:
Scotts-Bell 47 Inc
Model:
47D1 | 47G | 47G-2 | 47H-1
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: 70-14-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-1065

AD NUMBER:   70-14-01

SUBJECT HEADING:   Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective August 17, 1970.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
70-14-01 BELL: Amdt. 39-1022 as amended by Amendment 39-1065. Applies to all Bell Model 47D-1, 47G, 47G-2, and 47H-1 helicopters certificated in all categories and to any other helicopters equipped with duplex pitch change bearings, P/N 47-641-131-1.

Compliance required as indicated.

To prevent possible failure of tail rotor duplex pitch change bearing and to correct any improper installation of the duplex bearing and delta hinge bolts:

(a) Inspect all duplex pitch change bearings within the next 50 hours time in service after the effective date of this AD, unless already accomplished, as follows:

(1) Remove tail rotor assembly.

(2) Remove and disassemble the tail rotor drive head assembly to expose the duplex bearings and guide sleeve, P/N 47-641-040 or 47-641-130.

(3) Inspect the outside surface of the guide sleeve for scoring.

(4) Inspect the duplex bearing for roughness.

(5) Replace the duplex bearing before further flight as specified in subparagraphs (b)(3) and (4) if the guide sleeve is scored or if the bearing is rough.

(6) Install the tail rotor assembly and check rigging and tracking as described in subparagraph (b)(5).

(b) Remove and replace duplex pitch change bearings with 450 or more hours time in service on the effective date of this AD within the next 150 hours time in service, as follows:

(1) Remove tail rotor assembly,

(2) Remove and disassemble the tail rotor drive head assembly,

(3) Assemble and install the tail rotor drive head assembly, using a new duplex bearing, P/N 47-641-131-1, in accordance with the procedures specified in Paragraphs 6.63(j) and (k) in the Model 47D-1, 47G, and 47G-2 Maintenance and Overhaul Instruction Manual, as revised August 15, 1961, or in accordance with FAA approved equivalent procedures.

(4) Lubricate the bearing and sleeve with grease, MIL-G-25537 or equivalent.

(5) Install the tail rotor assembly and check rigging and tracking in accordance with the procedures specified in Paragraphs 6-17(a) through (h) or 6-18(a) through (g) of the appropriate manual or in accordance with FAA approved equivalent procedures.

(c) Remove and replace duplex pitch change bearings with less than 450 hours time in service on the effective date of this AD prior to accumulating 600 hours time in service, in accordance with the procedures described in subparagraphs (b)(1) through (5) above.

(d) Remove and replace all replacement duplex pitch change bearings prior to accumulating 600 hours time in service.

Amendment 39-1022 effective August 10, 1970.
This Amendment (39-1065) becomes effective August 17, 1970.

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Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_70-14-01.html
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Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
70-14-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters
Subject:
Tail Rotor Pitch
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/17/1970
Make:
Scotts-Bell 47 Inc
Model:
47D1 | 47G | 47G-2 | 47H-1
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: 70-14-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-1065

AD NUMBER:   70-14-01

SUBJECT HEADING:   Airworthiness Directives; Bell Model 47D-1, 47G, 47G-2, and 47H-1 Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective August 17, 1970.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
70-14-01 BELL: Amdt. 39-1022 as amended by Amendment 39-1065. Applies to all Bell Model 47D-1, 47G, 47G-2, and 47H-1 helicopters certificated in all categories and to any other helicopters equipped with duplex pitch change bearings, P/N 47-641-131-1.

Compliance required as indicated.

To prevent possible failure of tail rotor duplex pitch change bearing and to correct any improper installation of the duplex bearing and delta hinge bolts:

(a) Inspect all duplex pitch change bearings within the next 50 hours time in service after the effective date of this AD, unless already accomplished, as follows:

(1) Remove tail rotor assembly.

(2) Remove and disassemble the tail rotor drive head assembly to expose the duplex bearings and guide sleeve, P/N 47-641-040 or 47-641-130.

(3) Inspect the outside surface of the guide sleeve for scoring.

(4) Inspect the duplex bearing for roughness.

(5) Replace the duplex bearing before further flight as specified in subparagraphs (b)(3) and (4) if the guide sleeve is scored or if the bearing is rough.

(6) Install the tail rotor assembly and check rigging and tracking as described in subparagraph (b)(5).

(b) Remove and replace duplex pitch change bearings with 450 or more hours time in service on the effective date of this AD within the next 150 hours time in service, as follows:

(1) Remove tail rotor assembly,

(2) Remove and disassemble the tail rotor drive head assembly,

(3) Assemble and install the tail rotor drive head assembly, using a new duplex bearing, P/N 47-641-131-1, in accordance with the procedures specified in Paragraphs 6.63(j) and (k) in the Model 47D-1, 47G, and 47G-2 Maintenance and Overhaul Instruction Manual, as revised August 15, 1961, or in accordance with FAA approved equivalent procedures.

(4) Lubricate the bearing and sleeve with grease, MIL-G-25537 or equivalent.

(5) Install the tail rotor assembly and check rigging and tracking in accordance with the procedures specified in Paragraphs 6-17(a) through (h) or 6-18(a) through (g) of the appropriate manual or in accordance with FAA approved equivalent procedures.

(c) Remove and replace duplex pitch change bearings with less than 450 hours time in service on the effective date of this AD prior to accumulating 600 hours time in service, in accordance with the procedures described in subparagraphs (b)(1) through (5) above.

(d) Remove and replace all replacement duplex pitch change bearings prior to accumulating 600 hours time in service.

Amendment 39-1022 effective August 10, 1970.
This Amendment (39-1065) becomes effective August 17, 1970.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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