EASA AD CF-2019-23
Flight Controls — Pitch Trim System — Upgrade of the Horizontal Stabilizer Trim Electronic Control Unit
Summary
Canadian Airworthiness Directive CF-2019-23 mandates an upgrade to the Horizontal Stabilizer Trim Electronic Control Unit (HSTECU) on Bombardier Inc. BD-100-1A10 aircraft, serial numbers 20001 through 20337. This directive addresses the pitch trim system to enhance flight control safety by verifying the Motor Brake Assemblies' braking capability during power-up tests. The AD applies specifically to certain HSTECU part numbers installed on these aircraft.
What Changed
CF-2019-23 introduces a mandatory software upgrade for the HSTECU on affected Bombardier BD-100-1A10 aircraft. It requires verification of installed HSTECU part numbers and prohibits the installation of older HSTECU versions without the upgrade. The upgrade ensures the no-back mechanism and motor brake assemblies function correctly to prevent potential loss of the airplane due to pitch trim system failure.
Why It Matters
This directive is critical for aviation professionals because it addresses a safety risk related to the pitch trim system's horizontal stabilizer actuator. Operators and maintenance teams must ensure compliance to prevent possible loss of aircraft control caused by malfunctioning trim actuators. Compliance ensures continued airworthiness and regulatory adherence, reducing operational risks and enhancing passenger safety.
What To Do
Operators of Bombardier BD-100-1A10 aircraft must verify the HSTECU part number within 100 flight hours or 60 days from July 2, 2019, whichever occurs first. If the HSTECU is one of the specified older part numbers, they must upgrade it following Bombardier Service Bulletin 100-27-15 Revision 1 or later approved revisions. Installation of older HSTECU part numbers is prohibited after the effective date of this directive.
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