Service Difficulty Advisory

AV 2004-04
16 July 2004

Rolls Royce Corporation (RRC) 250 Series Engines

Engine Compressor Splined Adaptor Couplings

Transport Canada has received Special Airworthiness Information Bulletins (SAIB) NE-04-56, NE-04-57 and NE-04-58 from the Federal Aviation Administration (FAA) advising owners, operators, and repair stations of numerous failures of the subject adaptor couplings.

The reported failures were mostly due to fatigue originating from fretting on the outer diameter of the splined adaptor coupling where it mates with the compressor impeller. The subject couplings are part of the shafting system located between the gas generator turbine and the compressor. Both engine manufacturer parts and FAA approved PMA parts are referenced in the above FAA SAIBs.

Failure of this adaptor coupling results in immediate and total loss of power from the engine.

A review of the Service Difficulty database (USA, Canada &Australia) has revealed a number of previous SDRs submitted on the subject splined adaptors.

Known Engine models affected are as follows:

RRC 250-C20, -C20B, -C20J, -C20F, -C20W, -C20S and 250-B17 series engines.

These engines are installed on, but not limited to the following rotorcraft:

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

Transport Canada highly recommends that operators, AMEs and other responsible persons refer to aforementioned FAA publication SAIB NE-04-56, NE-04-57 and NE-04-58, dated March 24, 2004, in order to determine applicability to their own specific aeronautical products.

The subject SAIBs can be found at FAA website:

http://www.faa.gov/

Any further defects or occurrences should be reported to Transport Canada, Continuing Airworthiness, Ottawa via the Service Difficulty Reporting program.

For further information contact a Transport Canada Centre, or call Mr. Barry Caldwell, Continuing Airworthiness, Ottawa, telephone (613) 952-4358, facsimile (613) 996-9178 or e-mail caldweb@tc.gc.ca.

For Director, Aircraft Certification

B. Goyaniuk
Chief, Continuing Airworthiness

Note: For the electronic version of this document, please consult the following Web address:http://www.tc.gc.ca/eng/civilaviation/certification/menu.htm