SAIB NE-04-57

SPECIAL

AIRWORTHINESS

INFORMATION

BULLETIN

Aircraft Certification Service Washington, DC

U.S. Department of Transportation Federal Aviation Administration

NE-04-57 March 24, 2004 www.faa.gov/certification/aircraft This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin advises owners, operators, and repair stations of recently issued service information regarding Alcor Engine Company’s compressor splined adapter coupling, part number 23039791AL-1, -2, -3.produced under FAA Parts Manufacturer Approval (PMA) as replacement parts for certain (see below) Rolls-Royce Corporation (RRC) [formerly Allison Engine Company] Model 250 series engines.

Manufacturer Model(s) Rolls-Royce Corporation (RRC) 250- C20 and 250-B17 series engines Installed on, but not limited to:

Augusta A109, A109A and A109A II B-N Group Ltd. BN-2T Bell 206A, 206B and 206L Enstrom TH-28, 480 and 480B MDHI 369D, 369E, 369H, 369HM, 369HS and 369HE Eurocopter Deutschland BO-105C and BO-105S Eurocopter France AS355E, AS355F, AS355F1 and AS355F2 Schweizer 269D

Background

We have received reports of failure of Rolls-Royce and EXTEX compressor splined adapter couplings. The failure was due to fatigue originating from fretting on the outer diameter of the coupling where it mates with the compressor impeller. The compressor splined adapter coupling is part of the shafting system between the gas generator turbine and the compressor. Failure of this part results in immediate and total loss of power from the engine. There have been no reported failures of the Alcor compressor splined adapter coupling. However, we are issuing this SAIB on the Alcor coupling due to its identicality to the RRC coupling.

Alcor has issued Service Letter Bulletin (SLB) No. 814-3-1, Revision B, dated March 15, 2004, which recommends removal, inspection, and replacement of their compressor splined adapter coupling at next access to the coupling not to exceed 600 hours from the date of release of the above mentioned SLB.

Analysis is continuing and we are considering a number of alternatives, including mandatory action related to the above service document.

2 For Further Information Contact

Robert Baitoo, Aerospace Engineer, FAA Los Angeles Aircraft Certification Office, Propulsion Branch, ANM-140L; 3960 Paramount Boulevard, Lakewood, CA 90712; phone: (562) 627-5245;

fax: (562) 627-5210; email: robert.baitoo@faa.gov.

For Service Bulletin Information Contact

Alcor Engine Company Inc., 1015 N. McQueen Road, Suite 167, Gilbert, AZ 85233;

phone: (480) 632-1039; fax: (480) 632-1046.