# AD 69-12-07: Magnesium Tail Boom

- Type: Airworthiness directive
- Status: Current
- Products: Bell Helicopter Textron Canada 206A
- Effective: July 21, 1969
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-781
- Registered aircraft: 23 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F17C4AA68C2E6F4B86256A3400524047.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/69-12-07

## The airworthiness directive

69-12-07 BELL: Amdt. 39-781. Applies to Bell Model 206A helicopters, Serial Nos. 4 through 153, equipped with the magnesium tail boom assembly, Part No. 206-031-004-1 or -3.

Compliance required as indicated.

To prevent failure of the magnesium tail boom due to fatigue cracks, accomplish the following:

  (a) Before the first flight of each day after the effective date of this AD:

  (1) Remove the tail rotor drive shaft cover.

  (2) Inspect the skin adjacent to the rivet holes for cracks in the following areas, using a three-power or higher magnifying glass:

    (i) The tab attachment of the drive shaft cover to the tail boom.

    (ii) The area adjacent to the rivnut attachment of the tail rotor gear box fairing to the tail boom.

    (iii) The horizontal stabilizer attachment fittings.

  (3) Repair tail booms with only one skin crack less than one inch in length if the crack is located in an area described in (a)(2)(ii) or (iii) above, by stop drilling and deburring the holes.

  (4) Remove and replace tail booms with any other skin crack, in accordance with Paragraphs 8-37 through 8-47 of the Model 206A Maintenance and Overhaul Instructions.

  (b) Within 25 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 25 hours' time in service from the last inspection:

  (1) Remove the tail rotor drive shaft cover and the gear box fairing.

  (2) Inspect the skin adjacent to the rivet holes for cracks in the following areas, using a three-power or higher magnifying glass:

    (i) The tab attachment of the drive shaft cover to the tail boom.

    (ii) The rivnut attachments of the tail rotor gear box fairing to the tail boom.

    (iii) The horizontal stabilizer attachment fittings.

  (3) Repair tail booms with only one skin crack less than one inch in length if the crack is located in an area described in (b)(2)(ii) or (iii) above, by stop drilling and deburring theholes.

  (4) Remove and replace tail booms with any other skin crack, in accordance with Paragraphs 8-37 through 8-47 of the Model 206A Maintenance and Overhaul Instructions, before further flight.

  (5) Inspect tail rotor balance and balance, if necessary, in accordance with Paragraph 2A on Page 2 of Bell Service Bulletin No. 206A-7 dated August 22, 1968, or later FAA-approved revision or in accordance with an equivalent procedure approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, Federal Aviation Administration.

  (c) Remove and replace magnesium tail booms with 400 or more hours' time in service on the effective date of this AD within 100 hours' time in service therefrom.

  (d) Remove and replace magnesium tail booms with less than 400 hours' time in service on the effective date of this AD, prior to accumulating 500 hours' time in service.

  (e) Remove and replace all subsequent replacement magnesium tail booms prior to accumulating 500 hours' time in service.

(Bell Helicopter Company Service Bulletin No. 206A-7 dated August 22, 1968, pertains to this subject). This amendment becomes effective July 21, 1969.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS H2SW](https://openairdocs.org/tcds/H2SW): Bell Textron Canada Limited; names 1 of 12 models: 206A

## 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: 23 (23 by airframe model, 0 by engine model)
- Makers: Bell 23

Models with the most aircraft:

- [Bell 206A](https://openairdocs.org/model/bell-206a): 23 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/69-12-07/models.md
Every aircraft: https://openairdocs.org/ad/69-12-07/aircraft.md

Its text cites no advisory circulars or STCs.

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