# AD 79-02-04: Tail Rotor Drive Shaft

- Type: Airworthiness directive
- Status: Current
- Products: Agusta A109, A109A, A109, A109A, A109 and A109A
- Effective: February 19, 1979
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-3396
- Registered aircraft: 9 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/67B2F43C5398BE7386256A340047BC8E.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/79-02-04

## The airworthiness directive

79-02-04 COSTRUZIONI AERONAUTICHE GIOVANNI AGUSTA: Amendment 39- 3396. Applies to Model A109 and A109A helicopters, serial numbers 7109 and below, certificated in all categories, incorporating tail rotor drive shaft hanger bearing support bracket, P/N 109-0370-02-1.

Compliance is required as indicated, unless already accomplished.

To prevent a possible tail rotor failure, accomplish the following:

  (a) Within the next 10 hours time in service after the effective date of this AD, and thereafter following the last flight of each day in which the helicopter is operated, inspect the tail rotor drive shaft hanger bearing support bracket, P/N 109-0370-02-1, for cracks in accordance with Part I of the "Accomplishment" paragraph of Agusta Bollettino Tecnico No. 109-2, dated April 14, 1976, including Rev. A dated May 11, 1976, or an FAA-approved equivalent (hereinafter referred to as Service Bulletin).

  (b) If a crack is found during an inspection required by this AD, before further flight, except as provided in paragraph (d) of this AD, replace the affected bracket with -

  (1) A serviceable bracket of the same part number, and continue to inspect in accordance with paragraph (a) of this AD after the last flight of each day in which the helicopter is operated; or,

  (2) A new support bracket, P/N 109-0370-12-1, in accordance with Part II of the "Accomplishment" paragraph of the Service Bulletin.

  (c) Within the next 100 hours time in service after the effective date of this AD, replace the support bracket, P/N 109-0370-02-1 with a new bracket, P/N 109-0370-12-1, in accordance with Part II of the "Accomplishment" paragraph of the Service Bulletin. The repetitive inspections required by paragraphs (a) and (b)(1) of this AD may be discontinued upon installation of a support bracket, P/N 109-0370-12-1, in accordance with this AD.

  (d) Helicopters may be flown in accordance with FAR's 21.197 and 21.199 to a base where the required work canbe performed.

This amendment becomes effective February 19, 1979.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS H7EU](https://openairdocs.org/tcds/H7EU): Leonardo S.p.A.; names 2 of 10 models: A109, A109A

## 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: 9 (9 by airframe model, 0 by engine model)
- Makers: Agusta 8, Agusta-Bell 1

Models with the most aircraft:

- [Agusta A109A](https://openairdocs.org/model/agusta-a109a): 5 aircraft (airframe model)
- [Agusta AGUSTA A109](https://openairdocs.org/model/agusta-agusta-a109): 3 aircraft (airframe model)
- [Agusta-Bell A 109A](https://openairdocs.org/model/agusta-bell-a-109a): 1 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/79-02-04/models.md
Every aircraft: https://openairdocs.org/ad/79-02-04/aircraft.md

Its text cites no advisory circulars or STCs.

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