Challenger 300: AD 2012-06-03 Issued for Potential Dormant Failures

April 2012

The FAA has issued AD 2012-06-03 due to reports that the horizontal stabilizer trim actuator (HSTA) no-back and the number 1 motor brake assembly (MBA) on the Challenger 300 can both fail in a dormant condition, requiring an additional inspection requirement. Within 30 days after the effective date of the AD (May 10, 2012), you must add Task 27-41-05-105 to the aircraft maintenance program, which revises the aircraft maintenance schedule to include new functional tests of the HSTA no-back and HSTA brake system. Compliance is mandatory and testing will detect a dormant failure. If this condition remains unchecked, there is a possibility it could result in an uncontrollable horizontal stabilizer surface runaway without the ability to retrim, and consequent loss of the airplane.

Time Limits/Maintenance Checks

As of the May 10, 2012, effective date:

Task 27-41-05-105

The added functional test of the HSTA brake system must be incorporated in accordance with Bombardier Temporary Revision 5-2-59, dated November 25, 2010, to Section 5-10-40, of Part 2, of the Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual.

For this task, the initial compliance time starts are as follows:

Duncan Aviation has engineered the tooling necessary to comply with this AD. Ahead of the FAA issuance of this AD, a qualified Tech Rep and this tooling has already been dispatched to locations around the world for compliance.

Plan ahead and schedule your function test now. We anticipate a high demand. The longer you wait to schedule, the longer you’ll wait for the tooling to become available.