AD 75-17-27
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105A | Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105C | Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C Helicopters |
Unsafe Condition
Development of incipient cracks, corrosion, and excessive wear on bolts of the main rotor head.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Determine part number of Blade Mounting Bolts and replace P/N 105-14101.31 with P/N 105-14101.29. For Main Rotor Head Assemblies with Serial Number 50 or lower, replace Main Rotor Bolts P/N 105-14101.22 and .23 with revision letter 'g' or subsequent if bolts have revision 'a' through 'f'.
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Compliance Time
within the next 100 hours time in service after the effective date of this AD
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Affected Aircraft
Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C helicopters incorporating Main Rotor Head Assembly No. 105-14101
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Federal Register Abstract
Main Rotor Head Assembly
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_75-17-27.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 75-17-27 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C Helicopters Subject: Main Rotor Head Assembly Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/20/1975 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Helicopters Deutschland GmbH Model: BO-105A | BO-105C Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 75-17-27 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-2332 AD NUMBER: 75-17-27 SUBJECT HEADING: Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C Helicopters ACTION: SUMMARY: DATES: Effective August 20, 1975. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 75-17-27 MESSERSCHMITT-BOLKOW-BLOHM: Amendment 39-2332. Applies to Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C helicopters, certificated in all categories, incorporating Main Rotor Head Assembly No. 105-14101. Compliance is required within the next 100 hours time in service after the effective date of this AD, unless already accomplished in accordance with MBB BO-105 Alert Service Bulletin No. 4 and Service Bulletin No. 10-11. To prevent development of incipient cracks, corrosion, and excessive wear on bolts of the main rotor head, accomplish the following: (a) For all Main Rotor Head Assemblies, P/N 105-14101, determine part number of Blade Mounting Bolts. If bolt P/N 105-14101.31 is found, replace with serviceable bolt of P/N 105-14101.29. (b) For Main Rotor Head Assemblies 105-14101 having Serial Number 50 or lower, determine part number revision letter of Main Rotor Bolts P/N 105-14101.22 and .23. If any bolt with revision letter "a" through "f" is found, replace with serviceable bolt of the same part number having revision letter "g" or subsequent. This amendment becomes effective August 20, 1975. FOOTER:
Document Text
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AD Final Rules - DRS_75-17-27.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 75-17-27 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C Helicopters Subject: Main Rotor Head Assembly Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/20/1975 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: AIRWORTHINESS DIRECTIVES FINAL RULES: 75-17-27 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-2332 AD NUMBER: 75-17-27 SUBJECT HEADING: Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C Helicopters ACTION: SUMMARY: DATES: Effective August 20, 1975. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 75-17-27 MESSERSCHMITT-BOLKOW-BLOHM: Amendment 39-2332. Applies to Messerschmitt-Bolkow-Blohm (MBB) Models BO-105A and BO-105C helicopters, certificated in all categories, incorporating Main Rotor Head Assembly No. 105-14101. Compliance is required within the next 100 hours time in service after the effective date of this AD, unless already accomplished in accordance with MBB BO-105 Alert Service Bulletin No. 4 and Service Bulletin No. 10-11. To prevent development of incipient cracks, corrosion, and excessive wear on bolts of the main rotor head, accomplish the following: (a) For all Main Rotor Head Assemblies, P/N 105-14101, determine part number of Blade Mounting Bolts. If bolt P/N 105-14101.31 is found, replace with serviceable bolt of P/N 105-14101.29. (b) For Main Rotor Head Assemblies 105-14101 having Serial Number 50 or lower, determine part number revision letter of Main Rotor Bolts P/N 105-14101.22 and .23. If any bolt with revision letter "a" through "f" is found, replace with serviceable bolt of the same part number having revision letter "g" or subsequent. This amendment becomes effective August 20, 1975. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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