# AD 78-07-04: Inner Bevel Gear Assembly

- Type: Airworthiness directive
- Status: Current
- Products: Honeywell International T5508D
- Effective: March 30, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-3166
- Registered aircraft: 9 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D5B39E719DCB2F3C8625682C00769AF4.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/78-07-04

## The airworthiness directive

78-07-04 AVCO LYCOMING: Amendment 39-3166. Applies to Avco Lycoming T5508D model turboshaft engines. Compliance is required by May 1, 1978. To prevent fatigue failure of the engine accessory inner bevel gear leading to engine stoppage, remove inner bevel gear P/N 2-070-005-02 and replace with inner bevel gear assembly P/N 2-070-030-01, in accordance with Avco Lycoming Service Bulletin No. 5508-0013, dated March 15, 1978, or later revision approved by the Chief, Engineering and Manufacturing Branch, FAA, New England Region. The manufacturer's service bulletin identified and described in this directive is 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 Avco Lycoming Division, 550 South Main Street, Stratford, Connecticut 06497. These documents may also be examined at Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, and FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. This amendment becomes effective March 30, 1978.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E4NE](https://openairdocs.org/tcds/E4NE): Honeywell Aerospace US LLC; names 1 of 2 models: T5508D

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

Models with the most aircraft:

- [Lycoming T5508D](https://openairdocs.org/engine/lycoming-t5508d): 6 aircraft (engine model)
- [Honeywell T5508D](https://openairdocs.org/engine/honeywell-t5508d): 3 aircraft (engine model)

All 2 models: https://openairdocs.org/ad/78-07-04/models.md
Every aircraft: https://openairdocs.org/ad/78-07-04/aircraft.md

Its text cites no advisory circulars or STCs.

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