AD 90-23-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105C | Airworthiness Directives; MESSERSCHMITT-BOLKOW-BLOHM (MBB) Model BO105C and BO105S Series Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105S | Airworthiness Directives; MESSERSCHMITT-BOLKOW-BLOHM (MBB) Model BO105C and BO105S Series Helicopters |
Unsafe Condition
Engine flameout resulting from ingestion of layers of wet snow in engine inlets.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install a continuous ignition system per MBB SB-BO 105-80-108, incorporate FAA-approved RFM Revision No. 2/16 with specified paragraphs, and ensure engine inlet deflector shield is installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Required as indicated, unless already accomplished.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
All MBB Model BO105C and BO105S series helicopters certified in any category that operate in snow conditions.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Continuous Ignition System
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_90-23-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 90-23-08 Document Type: AD Final Rules Docket Number: 89-ASW-68 Subject Heading: Airworthiness Directives; MESSERSCHMITT-BOLKOW-BLOHM (MBB) Model BO105C and BO105S Series Helicopters Subject: Continuous Ignition System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/03/1990 Make: Airbus Helicopters Deutschland GmbH Model: BO-105C | BO-105S Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 90-23-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 89-ASW-68 AMENDMENT: 39-6778 AD NUMBER: 90-23-08 SUBJECT HEADING: Airworthiness Directives; MESSERSCHMITT-BOLKOW-BLOHM (MBB) Model BO105C and BO105S Series Helicopters ACTION: SUMMARY: DATES: Effective December 3, 1990. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 90-23-08 MESSERSCHMITT-BOLKOW-BLOHM (MBB): Amendment 39-6778. Docket No. 89-ASW-68. Applicability: All MBB Model BO105C and BO105S series helicopters, certified in any category, that operate in snow conditions. Compliance: Required as indicated, unless already accomplished. To prevent engine flameout resulting from ingestion of layers of wet snow in engine inlets, accomplish the following: (a) Install a continuous ignition system in accordance with MBB Service Bulletin, SB-BO 105-80-108, "Optional Equipment-Retrofit of Continuous Ignition System," dated May 11, 1990. (b) Incorporate into the applicable Rotorcraft Flight Manual (RFM) the FAA- approved flight manual Revision No. 2/16, dated October 1, 1989, which includes the following paragraphs 2.8.2.4 and 2.8.2.5: 2.8.2.4 Snow Conditions Operation in snow is prohibited, except when the Continuous Ignition System) OPT 19 is installed and switched on. Prior to takeoff, snow and ice must be removed, particularly from the following areas: - cabin roof - transmission cowling interior in front of engine air intakes - transmission compartment interior - engine inlet deflector shield. NOTE: After engine operation in snow make an entry in the logbook. Maintenance action is required in accordance with the Allison Operation and Maintenance Manual. 2.8.2.5 Engine Inlet Deflector Shield The engine inlet deflector shield must be installed at all times. The procedures shall be done in accordance with MBB Service Bulletin SB-BO 105-80- 108, which incorporates the following pages: 1, 2, and 8, Rev. 1, dated May 11, 1990; 3-7 and 9, Original, dated June 12, 1989. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from MBB Helicopter Corporation, 900 Airport Road, P.O. Box 2345, West Chester, PA 19380. Copies may be inspected at the Office of the Assistant Chief Counsel, FAA, 4400 Blue Mound Road, Fort Worth, Texas, or at the Office of the Federal Register, 1100 L Street, NW., Room 8301, Washington, DC. This amendment (39-6778, AD 90-23-08) becomes effective on December 3, 1990. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_90-23-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 90-23-08 Document Type: AD Final Rules Docket Number: 89-ASW-68 Subject Heading: Airworthiness Directives; MESSERSCHMITT-BOLKOW-BLOHM (MBB) Model BO105C and BO105S Series Helicopters Subject: Continuous Ignition System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/03/1990 Make: Airbus Helicopters Deutschland GmbH Model: 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: 90-23-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 89-ASW-68 AMENDMENT: 39-6778 AD NUMBER: 90-23-08 SUBJECT HEADING: Airworthiness Directives; MESSERSCHMITT-BOLKOW-BLOHM (MBB) Model BO105C and BO105S Series Helicopters ACTION: SUMMARY: DATES: Effective December 3, 1990. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 90-23-08 MESSERSCHMITT-BOLKOW-BLOHM (MBB): Amendment 39-6778. Docket No. 89-ASW-68. Applicability: All MBB Model BO105C and BO105S series helicopters, certified in any category, that operate in snow conditions. Compliance: Required as indicated, unless already accomplished. To prevent engine flameout resulting from ingestion of layers of wet snow in engine inlets, accomplish the following: (a) Install a continuous ignition system in accordance with MBB Service Bulletin, SB-BO 105-80-108, "Optional Equipment-Retrofit of Continuous Ignition System," dated May 11, 1990. (b) Incorporate into the applicable Rotorcraft Flight Manual (RFM) the FAA- approved flight manual Revision No. 2/16, dated October 1, 1989, which includes the following paragraphs 2.8.2.4 and 2.8.2.5: 2.8.2.4 Snow Conditions Operation in snow is prohibited, except when the Continuous Ignition System) OPT 19 is installed and switched on. Prior to takeoff, snow and ice must be removed, particularly from the following areas: - cabin roof - transmission cowling interior in front of engine air intakes - transmission compartment interior - engine inlet deflector shield. NOTE: After engine operation in snow make an entry in the logbook. Maintenance action is required in accordance with the Allison Operation and Maintenance Manual. 2.8.2.5 Engine Inlet Deflector Shield The engine inlet deflector shield must be installed at all times. The procedures shall be done in accordance with MBB Service Bulletin SB-BO 105-80- 108, which incorporates the following pages: 1, 2, and 8, Rev. 1, dated May 11, 1990; 3-7 and 9, Original, dated June 12, 1989. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from MBB Helicopter Corporation, 900 Airport Road, P.O. Box 2345, West Chester, PA 19380. Copies may be inspected at the Office of the Assistant Chief Counsel, FAA, 4400 Blue Mound Road, Fort Worth, Texas, or at the Office of the Federal Register, 1100 L Street, NW., Room 8301, Washington, DC. This amendment (39-6778, AD 90-23-08) becomes effective on December 3, 1990. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2025-25-05
final ruleAirworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters
Unsafe Condition: Crack found on the fork lever of the mixing lever assembly, which could result in failure of the fork lever and consequent loss of control of the helicopter.
2024-20-07 Recurring
final ruleAirworthiness Directives; Various Helicopters
Unsafe Condition: Difficulty pulling the emergency float kit activation handle installed on the pilot cyclic, and deficiencies in the installation of the cables on the emergency float kits.
2023-11-07
final ruleAirworthiness Directives; Various Helicopters
Unsafe Condition: unsafe condition on these products.
2023-03-01
final ruleAirworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters
Unsafe Condition: A missing inner ring on the main rotor swashplate, which could result in loss of main rotor control and subsequent loss of control of the helicopter.
