# AD 81-13-12 R1: 4th Stage Turbine Nozzle Assembly

- Type: Airworthiness directive
- Status: Current
- Products: Rolls-Royce 250-C30, 250-C30P and 250-C30S
- Effective: September 26, 1983
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-4701
- Registered aircraft: 563 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/6F64BA252C31480B8625683F006C2AEA.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/81-13-12-R1

## The airworthiness directive

81-13-12 R1 DETROIT DIESEL ALLISON: Amendment 39-4179 as amended by Amendment 39-4701. Applies to all Model 250-C30, -C30P, and C30S engines and turbine assemblies equipped with 4th stage turbine nozzle assembly P/N 6898694 installed in aircraft certificated in all categories, EXCEPT:

1. Models 250-C30, -C30S: ENGINE SERIAL NO. TURBINE SERIAL NO. CAE 890690, 890691, CAT 95105, 95106, 890692, 890696, and subsequent 95108, 95109, and subsequent

2. Model 250-C30P: ENGINE SERIAL NO. TURBINE SERIAL NO. CAE 895086, 895087, and subsequent CAT 95110, 95111, 95112, and subsequent

Compliance is required as indicated unless already accomplished. To prevent cracks in P/N 6898694 4th stage turbine wheel nozzles leading to uncontained turbine wheel failures accomplish the following: a. Inspect, reduce life limits where applicable based on inspection results, and remove from service affected P/N 6898694 nozzles in compliance with the schedule, instructions, and inspection criteria provided in Detroit Diesel Allison Commercial Engine Alert Bulletin CEB-A-72-3056, Revision 3 dated March 30, 1983, or later FAA approved revisions. b. Special flight permits may be issued in accordance with FAR's 21.197 and 21.199 to operate aircraft to a base where compliance with this AD can be accomplished. c. Upon request of the operator, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Chicago Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018. The manufacturer's specifications and procedures identified and described in this directive are 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 Detroit Diesel Allison, Division of General Motors Corporation, Indianapolis, Indiana 46206. These documents also maybe examined at the Office of Regional Counsel, FAA, 12 New England Executive Park, Burlington, Massachusetts 01803 weekdays, except federal holidays, between 8:00 a.m. and 4:30 p.m. Amendment 39-4179 became effective August 10, 1981. This Amendment 39-4701 becomes effective September 26, 1983.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E1GL](https://openairdocs.org/tcds/E1GL): Rolls-Royce Corporation; names 3 of 23 models: 250-C30, 250-C30S, 250-C30P

## 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: 563 (0 by airframe model, 563 by engine model)
- Makers: Bell 282, Bell Helicopter Textron Canada 106, MD Helicopters 68, Bell Helicopter Textron 23, Hiller 15, Mcdonnell Douglas Heli 14, Sikorsky 10, Enstrom Helicopter 9, Cessna 7, Beech 6

Models with the most aircraft:

- [Allison 250-C30 series](https://openairdocs.org/engine/allison-250-c30-series): 224 aircraft (engine model)
- [Rolls-Royce 250-C30P](https://openairdocs.org/engine/rolls-royce-250-c30p): 152 aircraft (engine model)
- [Allison 250 series](https://openairdocs.org/engine/allison-250-series): 79 aircraft (engine model)
- [Rolls-Royce 250-C30](https://openairdocs.org/engine/rolls-royce-250-c30): 76 aircraft (engine model)
- [Allison 250-C30P](https://openairdocs.org/engine/allison-250-c30p): 25 aircraft (engine model)
- [Allison 250-C30](https://openairdocs.org/engine/allison-250-c30): 5 aircraft (engine model)
- [Rolls-Royce 250-C30S](https://openairdocs.org/engine/rolls-royce-250-c30s): 2 aircraft (engine model)

All 8 models: https://openairdocs.org/ad/81-13-12-R1/models.md
Every aircraft: https://openairdocs.org/ad/81-13-12-R1/aircraft.md

Its text cites no advisory circulars or STCs.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.