# AD 69-26-03: Modify Power and Accessories Gear Box

- Type: Airworthiness directive
- Status: Current
- Products: Rolls-Royce 250-C18, 250-C18A, 250-C18B and 250-C18C
- Effective: December 25, 1969
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-895
- Registered aircraft: 84 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DFE8E71215F25892862568270065F840.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/69-26-03

## The airworthiness directive

69-26-03 ALLISON: Amdt. 39-895. Applies to Model 250-C18 Series Engines. Compliance: Unless already accomplished, accomplish the following: (1) At next overhaul but no later than 750 hours' time in service since last overhaul or since new if never overhauled, modify the engine in accordance with Allison Commercial Engine Bulletins numbered 250CEB-57, - 58, -59, -61, -62, -63, -65, -66, -67, -68, -69, -70, -72, -73, -74, -75, -76, -77, -78, -79, -80, -81, -85, -86 and -89, or an equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region, except as specified in (2) below. (2) At next overhaul but no later than 1125 hours' time in service since last overhaul or since new if never overhauled, modify the power and accessories gear box in accordance with applicable portions of Allison Commercial Engine Bulletins specified in (1) above, or an equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA Central Region.(3) All engines must be modified in accordance with (1) and (2) above on or before October 1, 1971. This amendment becomes effective December 25, 1969.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E4CE](https://openairdocs.org/tcds/E4CE): Rolls-Royce Corporation; names 4 of 23 models: 250-C18, 250-C18A, 250-C18B, 250-C18C

## 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: 84 (0 by airframe model, 84 by engine model)
- Makers: Bell 31, Hiller 15, Enstrom Helicopter 9, Cessna 7, Beech 6, Hughes 4, Siai-Marchetti 3, Ardoyno John W 1, Huizenga Mike 1, Maule 1

Models with the most aircraft:

- [Allison 250 series](https://openairdocs.org/engine/allison-250-series): 79 aircraft (engine model)
- [Allison 250-C18](https://openairdocs.org/engine/allison-250-c18): 2 aircraft (engine model)
- [Allison 250-C18B](https://openairdocs.org/engine/allison-250-c18b): 2 aircraft (engine model)
- [Rolls-Royce 250-C18](https://openairdocs.org/engine/rolls-royce-250-c18): 1 aircraft (engine model)

All 5 models: https://openairdocs.org/ad/69-26-03/models.md
Every aircraft: https://openairdocs.org/ad/69-26-03/aircraft.md

Its text cites no advisory circulars or STCs.

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