# AD 78-24-02: Main Transmission

- Type: Airworthiness directive
- Status: Current
- Products: Agusta A109, A109A, A109A II, A109C, A109E and A109K2
- Effective: November 24, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-3346
- Registered aircraft: 96 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/AB07E0A6C5A1FBDC86256A340047B3A1.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/78-24-02

## The airworthiness directive

78-24-02 COSTRUZIONI AERONAUTICHE GIOVANNI AGUSTA: Amendment 39- 3346. Applies to Agusta Model A109 Series helicopters, S/N 7107, 7111, 7126, and 7129, certificated in all categories.

Compliance required before further flight, unless already accomplished, but helicopter may be flown in accordance with FAR 21.197 and 21.199 to a base where the required work can be performed.

To prevent possible failure of main transmission P/N 109-0400-02-01, remove pinion gear P/N 109- 0403-06-01, S/N 18, 24, 25 or 27, from main transmissions S/N 31, 36, 11 and 10, respectively, and replace with new pinion gear of same part number having serial number other than 17 through 32.

This amendment is effective November 24, 1978, as to all persons except those persons to whom it was made immediately effective by the letter dated April 26, 1978, which contained this amendment

## 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 6 of 10 models: A109, A109A, A109E, A109K2, A109A II, A109C

## 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: 96 (96 by airframe model, 0 by engine model)
- Makers: Agusta 92, Agusta S P A 2, Agusta S P A Construzioni Aero 1, Agusta-Bell 1

Models with the most aircraft:

- [Agusta A109E](https://openairdocs.org/model/agusta-a109e): 55 aircraft (airframe model)
- [Agusta A109A II](https://openairdocs.org/model/agusta-a109a-ii): 17 aircraft (airframe model)
- [Agusta A109C](https://openairdocs.org/model/agusta-a109c): 12 aircraft (airframe model)
- [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 S P A A109K2](https://openairdocs.org/model/agusta-s-p-a-a109k2): 2 aircraft (airframe model)
- [Agusta-Bell A 109A](https://openairdocs.org/model/agusta-bell-a-109a): 1 aircraft (airframe model)
- [Agusta S P A Construzioni Aero A109E](https://openairdocs.org/model/agusta-s-p-a-construzioni-aero-a109e): 1 aircraft (airframe model)

All 8 models: https://openairdocs.org/ad/78-24-02/models.md
Every aircraft: https://openairdocs.org/ad/78-24-02/aircraft.md

Its text cites no advisory circulars or STCs.

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