Airworthiness Directive · Amendment 39-17894 · Instruments
Bombardier, Inc. Airplanes
This AD applies to Bombardier, Inc., Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes; certificated in any category; serial numbers 003 through 672 inclusive with a beta warning horn (BWH) (Mod 8/2852) incorporated; except for airplanes that have incorporated Bombardier option CR873CH00003, CR873CH00005, CR873SOO8112, or MS8Q902206.
We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-102, -103, and -106 airplanes; and DHC-8- 200 and DHC-8-300 series airplanes. This AD was prompted by a report of a beta warning horn (BWH) system failing to activate when the beta mode was triggered. This AD requires modifying the BWH microswitch installation. We are issuing this AD to prevent the inadvertent activation of ground beta mode during flight, which could lead to engine overspeed, engine damage or failure, and consequent reduced controllability of the airplane.
Within 6,000 flight hours or 36 months, whichever occurs first, after the effective date of this AD: Modify the BWH microswitch installation by replacing the existing BWH microswitch installation bracket with a new bracket having part number 87610164-003, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 8-76-33, dated December 13, 2012.
