PW305A Engine In-Flight Shutdown Events Due to Failure of Smiths Electronic Engine Control Units - Civil Aviation Safety Alert (CASA) No. 2021-09


Owners, operators and maintainers of Pratt & Whitney Canada (P&WC) PW305A engines installed on Learjet 60 aircraft serial numbers 001 through 128

File Classification No.: Z 5000-35
RDIMS No.: 17236429
Document No.: CASA 2021-09
Issue No.: 01
Effective Date: 2021-06-16


The purpose of this Civil Aviation Safety Alert (CASA) is to raise awareness of an increased rate of in-flight shut down (IFSD) events on PW305A engines installed with Electronic Engine Control (EEC) units manufactured by Smiths.


There has been a notable increase in recent years of engine IFSD events attributed to the failure of EEC units, part number (P/N) 31B4741 (vendor P/N 1240KDC) manufactured by Smiths. Investigation by P&WC has shown that the failures can be attributed to an aging effect of internal EEC components. In addition, P&WC support for the repair of these older EEC units, manufactured by Smiths, will no longer be possible in the near future. As a result, P&WC has issued Service Information Letter (SIL) PW300-201 recommending an upgrade to the latest EEC configuration in accordance with P&WC Service Bulletin PW300-72-24434.

Recommended action

Transport Canada recommends that owners, operators and maintainers of the affected PW305A engines familiarize themselves with P&WC’s SIL PW300-201 and follow the recommendations therein.

Contact office:

For more information concerning this issue, contact a Transport Canada Centre; or contact Robert Farinas, Continuing Airworthiness in Ottawa, by telephone at 1-888-663-3639, by facsimile at 613-996-9178 or by e-mail at TC.CAWWEBFEEDBACK-retroactionWebMDLN.TC@TC.GC.CA.

Original signed by

Rémy Knoerr
Chief, Continuing Airworthiness
National Aircraft Certification

The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.