AD 75-14-02

final rule

Airworthiness Directives; Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters

AD Number
75-14-02
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 Boelkow Blohm (MBB) Model BO-105 Helicopters
aircraft Airbus Helicopters Deutschland GmbH BO-105C Airworthiness Directives; Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters

Unsafe Condition

Failure in service of main rotor hub quadruple nuts due to cracks resulting from manufacturing defects.

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

Required Actions

Determine the production lot number of the installed main rotor hub quadruple nuts (P/N 105-14101.19 and .20) within twenty hours time in service after the effective date. If the lot number is 06, 07, or cannot be determined, remove and replace the quadruple nuts with serviceable parts of the same part number before further flight.

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

Compliance Time

within twenty hours time in service after the effective date

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

Affected Aircraft

Messerschmitt Boelkow Blohm (MBB) Model BO-105A and BO-105C helicopters certificated in all categories.

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

Federal Register Abstract

Rotor Hub Quadruple Nuts

Applicability Source Text

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AD Number:
75-14-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters
Subject:
Rotor Hub Quadruple Nuts
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Airbus Helicopters Deutschland GmbH
Model:
BO-105A | BO-105C
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Superseded AD: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Superseded By: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:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 75-14-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2246

AD NUMBER:   75-14-02

SUBJECT HEADING:   Airworthiness Directives; Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
75-14-02 MESSERSCHMITT BOELKOW BLOHM GMBH: Amendment 39-2246. Applies to Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters certificated in all categories.

Compliance is required as indicated.

To prevent failure in service of certain main rotor hub quadruple nuts due to cracks resulting from manufacturing defects, accomplish the following:

(a) Within the next twenty hours time in service after the effective date of this AD, determine the production lot number of the two installed main rotor hub quadruple nuts, P/N 105- 14101.19 and .20.

NOTE: Quadruple nuts are identified "VIERFACHNUSS" on P/N drawings. Production lot number of nuts is set forth as first two digits of serial number recorded in MBB individual aircraft historical record document, under the heading of Main Rotor Head Assembly No. 105-14101.

(b) If the lot number determined in accordance with paragraph (a) of this AD is 06 or 07, or if the lot number cannot be determined, before further flight, except that the aircraft may be flown in accordance with FAR Section 21.197 and 21.199 to a base where the work can be performed, remove the two quadruple nuts and replace with serviceable parts of the same part number.

(Messerschmitt Boelkow Blohn BO-105 Alert Service Bulletin No. 9 covers this same subject).

This amendment is effective upon publication in the Federal Register as to all persons except those persons to whom it was made immediately effective by the telegram dated May 14, 1975, which contained this amendment.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_75-14-02.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
75-14-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters
Subject:
Rotor Hub Quadruple Nuts
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Airbus Helicopters Deutschland GmbH
Model:
BO-105A | BO-105C
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:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 75-14-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2246

AD NUMBER:   75-14-02

SUBJECT HEADING:   Airworthiness Directives; Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
75-14-02 MESSERSCHMITT BOELKOW BLOHM GMBH: Amendment 39-2246. Applies to Messerschmitt Boelkow Blohm (MBB) Model BO-105 Helicopters certificated in all categories.

Compliance is required as indicated.

To prevent failure in service of certain main rotor hub quadruple nuts due to cracks resulting from manufacturing defects, accomplish the following:

(a) Within the next twenty hours time in service after the effective date of this AD, determine the production lot number of the two installed main rotor hub quadruple nuts, P/N 105- 14101.19 and .20.

NOTE: Quadruple nuts are identified "VIERFACHNUSS" on P/N drawings. Production lot number of nuts is set forth as first two digits of serial number recorded in MBB individual aircraft historical record document, under the heading of Main Rotor Head Assembly No. 105-14101.

(b) If the lot number determined in accordance with paragraph (a) of this AD is 06 or 07, or if the lot number cannot be determined, before further flight, except that the aircraft may be flown in accordance with FAR Section 21.197 and 21.199 to a base where the work can be performed, remove the two quadruple nuts and replace with serviceable parts of the same part number.

(Messerschmitt Boelkow Blohn BO-105 Alert Service Bulletin No. 9 covers this same subject).

This amendment is effective upon publication in the Federal Register as to all persons except those persons to whom it was made immediately effective by the telegram dated May 14, 1975, which contained this amendment.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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