# AD 85-26-02: Hydraulic Actuator - Type: Airworthiness directive - Status: Current - Products: Airbus Helicopters Deutschland BO-105A, BO-105C and BO-105S - Effective: February 25, 1986 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-5226 - Registered aircraft: 17 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/05CB2E1C9DCFC52C86256A4E0056289B.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/85-26-02 ## The airworthiness directive 85-26-02 MESSERSCHMITT-BOLKOW-BLOHM: Amendment 39-5226. Applies to Model BO-105 series helicopters, through serial No. 750, certificated in any category that are equipped with one of the following tandem hydraulic units: Part Numbers (P/N) 105-45021, 105- 45023, 105-45028, 105-83001, 105-83011, D133-3073, and DSK1-30142. Compliance is required as indicated, unless previously accomplished. To detect or prevent possible jamming of the helicopter main rotor control system, accomplish the following: (a) Before the first flight of each day after the effective date of this AD, operate the System II hydraulic actuators to detect binding of the control. If binding is detected, clean and seal the System II hydraulic actuators in accordance with paragraph (b) of this AD. (b) Within the next 10 hours time in service after the effective date of this AD, clean and seal the System II hydraulic actuators in accordance with MBB BO-105, ASB No. 26, Part 2B, dated December 12, 1985, or with an equivalent approved in accordance with paragraph D of this AD. After sealing, the operational check in paragraph (a) is no longer required. (c) The operational check in paragraph (a) may be performed by the pilot. NOTE: For the requirements regarding recording compliance and method of compliance with this AD in the aircraft's permanent maintenance records, see FAR Section 91.173. (d) Upon request, an equivalent means of compliance with this AD may be used when approved by the Manager, Aircraft Certification Office, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, Brussels, Belgium, APO NY 09667-1011. (e) The aircraft may be flown in accordance with FAR Sections 21.197 and 21.199 to a base where the actuators may be sealed in accordance with paragraph (b) of this AD. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to MBB Helicopter Corp., P.O. Box 2349, West Chester, Pennsylvania 19380. These documents may also be examined at the Office of the Regional Counsel, Federal Aviation Administration, Southwest Region, Room 158, Building 3B, 4400 Blue Mound Road, Fort Worth, Texas 76106. This amendment becomes effective February 25, 1986, as to all persons except those persons to whom it was made immediately effective by priority letter AD 85-26-02, issued December 23, 1985, which contained this amendment. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS H3EU](https://openairdocs.org/tcds/H3EU): Airbus Helicopters Deutschland GmbH (AHD); names 3 of 5 models: BO-105C, BO-105A, BO-105S ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 17 (17 by airframe model, 0 by engine model) - Makers: Messerschmitt-Boelkow-Blohm 11, Messerschmitt-Boelkow-Blohm-Gm 4, Eurocopter Deutschland 1, Messerschmitt Bolkow Blohm 1 Models with the most aircraft: - [Messerschmitt-Boelkow-Blohm BO-105S](https://openairdocs.org/model/messerschmitt-boelkow-blohm-bo-105s): 11 aircraft (airframe model) - [Messerschmitt-Boelkow-Blohm-Gm BO-105C](https://openairdocs.org/model/messerschmitt-boelkow-blohm-gm-bo-105c): 4 aircraft (airframe model) - [Messerschmitt Bolkow Blohm BO105S CBS-5](https://openairdocs.org/model/messerschmitt-bolkow-blohm-bo105s-cbs-5): 1 aircraft (airframe model) - [Eurocopter Deutschland BO 105S](https://openairdocs.org/model/eurocopter-deutschland-bo-105s): 1 aircraft (airframe model) All 4 models: https://openairdocs.org/ad/85-26-02/models.md Every aircraft: https://openairdocs.org/ad/85-26-02/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.