Installing a thrust reverser voice command warning system

Effectivity: Learjet 60/60XR

ATA: ​78 - Exhaust​

By: TJ Will—Customer Support Engineering  

Bombardier reminds operators of Service Bulletin 60-78-9, Thrust Reverser System Improvement, to install a Thrust Reverser (TR) Voice Command Warning System (VCWS). This is also the closing action to Airworthiness Directive FAA AD 2020-11-04.   

The FAA issued AD 2020-11-04 mandating the installation of a TR VCWS in the aircraft to alert operators of an abnormal thrust reverser configuration. The effective date of the AD was June 25, 2020, with a compliance time of 1,200 flight hours or 48 months, whichever comes first, putting the calendar deadline at June 25, 2024.   

Potential anomalies can occur where one or both TRs are not deployed when commanded; or, one or both may inadvertently stow uncommanded after being deployed. The flight crew may not be aware of the improper position of the TR doors. The service bulletin provides instructions to install the VCWS to alert the crew of a thrust reverser configuration malfunction.   

In addition to the service bulletin, a global Alternate Method of Compliance (AMOC) is provided to allow usage of Revision 1 of the service bulletin to show compliance with AD 2020-11-04. Service bulletin kits are available from Turbine Engine Specialists (TES).    

For additional information or questions, please contact your regional Field Service Representative.