# AD 85-08-01: Vertical Fin Spar And Skins

- Type: Airworthiness directive
- Status: Current
- Products: Airbus Helicopters Deutschland BO-105A, BO-105C and BO-105S
- Effective: April 26, 1985
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-5038
- Registered aircraft: 17 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/7FE11AFEA0E1A23186256A4E005621B1.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/85-08-01

## The airworthiness directive

85-08-01 MESSERSCHMITT-BOLKOW-BLOHM GmbH: Amendment 39-5038. Applies to Model BO-105 series helicopters, S/N's S1 through S350, certificated in all categories, that are equipped with empennage P/N 105-30101.

Compliance is required within 50 hours time in service after the effective date of this AD, unless already accomplished.

To prevent cracks in the vertical fin spar and skins and possible failure of the vertical fin, accomplish the following modifications:

  (a) For helicopters with S/N's S1 through S310, incorporate the tail fin modification and reinforcement specified in MBB BO-105 Service Bulletin No. 30-13, Rev. 2, dated April 24, 1978.

  (b) For helicopters with S/N's S1 through S350, incorporate the gearbox mount and upper fin modification specified in MBB BO-105 Service Bulletin No. 30-18, Rev. 3, dated October 30, 1984.

  (c) Aircraft may be flown in accordance with FAR Sections 21.197 and 21.199 to a base where compliance may be accomplished.

  (d)Equivalent means of complying with this AD must be approved by the Manager, Aircraft Certification Office, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, Brussels, Belgium.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part thereof 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 of the service bulletins upon request to MBB Helicopter Corporation, P.O. Box 2349, West Chester, Pennsylvania 19380. The documents also may be examined at the Office of the Regional Counsel, Southwest Region, Federal Aviation Administration, 4400 Blue Mound Road, Fort Worth, Texas.

This amendment becomes effective April 26, 1985.

## 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/85-08-01/models.md
Every aircraft: https://openairdocs.org/ad/85-08-01/aircraft.md

Its text cites no advisory circulars or STCs.

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