AD 77-11-02

final rule

Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters

AD Number
77-11-02
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 Airbus Helicopters Deutschland GmbH BO-105A Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters
aircraft Airbus Helicopters Deutschland GmbH BO-105C Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters
aircraft Airbus Helicopters Deutschland GmbH BO-105S Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters

Unsafe Condition

Failure of the main rotor hub quadruple nuts and associated bolts could result in loss of the main rotor.

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

Required Actions

Inspect main rotor hub quadruple nuts (P/N 105-14101.19, 105-14101.20) and bolts (P/N 105-14101.22, 105-14101.23) with over 1,400 hours time in service using magnaflux or FAA-approved equivalent. Replace cracked parts before flight. Replace nuts/bolts before 2,400 hours total time in service.

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

Compliance Time

Within the next 100 hours time in service after the effective date (June 14, 1977), unless already accomplished within the last 200 hours time in service. Thereafter at intervals not to exceed 300 hours time in service from the last inspection.

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

Affected Aircraft

Messerschmitt-Bolkow-Blohm GmbH Model BO-105A, BO-105C, BO-105S helicopters certificated in all categories.

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

Federal Register Abstract

Main Rotor

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_77-11-02.html
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AD Number:
77-11-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters
Subject:
Main Rotor
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
06/14/1977
Make:
Airbus Helicopters Deutschland GmbH
Model:
BO-105A | BO-105C | BO-105S
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: 77-11-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2912

AD NUMBER:   77-11-02

SUBJECT HEADING:   Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective June 14, 1977.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
77-11-02 MESSERSCHMITT-BOLKOW-BLOHM GmbH: Amendment 39-2912. Applies to Model BO-105 helicopters, certificated in all categories.

Compliance is required as indicated.

To prevent the possible failure of the main rotor hub quadruple nuts and the consequent loss of the main rotor, accomplish the following:

(a) For main rotor hub quadruple nuts, P/N's 105-14101.19 and 105-14101.20 and associated bolts, P/N's 105-14101.22 and 105-14101.23, with more than 1,400 hours total time in service, within the next 100 hours time in service after the effective date of this AD, unless already accomplished within the last 200 hours time in service, and thereafter at intervals not to exceed 300 hours time in service from the last inspection, remove the quadruple nuts and associated bolts and inspect them for cracks using a magnaflux process, or an FAA-approved equivalent.

(b) If a crack is found in a nut or bolt during any of the inspections required by this AD, before further flight, replace the cracked part with a serviceable part of the same part number. For parts installed as replacements, before the accumulation of 1,500 hours total time in service on the replacement parts and thereafter at intervals not to exceed 300 hours time in service from the last inspection, remove the replacement quadruple nuts and associated bolts and inspect them for cracks using a magnaflux process or an FAA-approved equivalent.

(c) Before the accumulation of 2,400 hours total time in service on a quadruple nut or bolt specified in paragraph (a) of this AD, replace the quadruple nuts and associated bolts with serviceable nuts and bolts of the same part numbers and comply with paragraphs (a) and (b) of this AD for the replacement parts.

(MBB Service Bulletin No. 10-18 dated July 18, 1975, covers this same subject.)

This amendment becomes effective June 14, 1977.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_77-11-02.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
77-11-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters
Subject:
Main Rotor
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
06/14/1977
Make:
Airbus Helicopters Deutschland GmbH
Model:
BO-105A | BO-105C | BO-105S
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: 77-11-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2912

AD NUMBER:   77-11-02

SUBJECT HEADING:   Airworthiness Directives; Messerschmitt-Bolkow-Blohm GmbH Model BO-105 Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective June 14, 1977.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
77-11-02 MESSERSCHMITT-BOLKOW-BLOHM GmbH: Amendment 39-2912. Applies to Model BO-105 helicopters, certificated in all categories.

Compliance is required as indicated.

To prevent the possible failure of the main rotor hub quadruple nuts and the consequent loss of the main rotor, accomplish the following:

(a) For main rotor hub quadruple nuts, P/N's 105-14101.19 and 105-14101.20 and associated bolts, P/N's 105-14101.22 and 105-14101.23, with more than 1,400 hours total time in service, within the next 100 hours time in service after the effective date of this AD, unless already accomplished within the last 200 hours time in service, and thereafter at intervals not to exceed 300 hours time in service from the last inspection, remove the quadruple nuts and associated bolts and inspect them for cracks using a magnaflux process, or an FAA-approved equivalent.

(b) If a crack is found in a nut or bolt during any of the inspections required by this AD, before further flight, replace the cracked part with a serviceable part of the same part number. For parts installed as replacements, before the accumulation of 1,500 hours total time in service on the replacement parts and thereafter at intervals not to exceed 300 hours time in service from the last inspection, remove the replacement quadruple nuts and associated bolts and inspect them for cracks using a magnaflux process or an FAA-approved equivalent.

(c) Before the accumulation of 2,400 hours total time in service on a quadruple nut or bolt specified in paragraph (a) of this AD, replace the quadruple nuts and associated bolts with serviceable nuts and bolts of the same part numbers and comply with paragraphs (a) and (b) of this AD for the replacement parts.

(MBB Service Bulletin No. 10-18 dated July 18, 1975, covers this same subject.)

This amendment becomes effective June 14, 1977.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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