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:

HSTA Total Flight Hours Compliance
2600 or fewer as of May 10, 2012 Prior to accumulating 3000 total flight hours.
More than 2600 as of May 10, 2012 Within 400 flight hours or by October 10, 2012, whichever occurs first.

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:

Aircraft Total Flight Hours Compliance
Less than 400 as of May 10, 2012 Prior to accumulating 800 total flight hours.
More than 400 as of May 10, 2012 Within 400 flight hours or by May 10, 2013, whichever occurs first.

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.

Scott Shefke Airframe Tech Rep Lincoln, NE (LNK)
+1 402.479.1681

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