Airworthiness Directive · Amendment 39-18692 · Propellers/propulsors
Bombardier, Inc. Airplanes
This AD applies to all Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category.
We are adopting a new airworthiness directive (AD) for all Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a revision by the manufacturer to the Certification Maintenance Requirements (CMR) of the Airworthiness Limitation Items (ALI), in the Maintenance Requirement Manual (MRM), that introduces a new CMR task that requires repetitive operational checks of the propeller overspeed governor. This AD requires revising the airplane maintenance or inspection program, as applicable, to incorporate a new CMR task. We are issuing this AD to prevent dormant failure of the propeller overspeed governor, which may lead to a loss of propeller overspeed protection and result in high propeller drag in flight.
Within 30 days after the effective date of this AD, revise the maintenance program or inspection program, as applicable, to incorporate an operational check of the propeller overspeed governor, CMR task number 612000-109, to be performed every 200 flight hours, using a method approved by the Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA.
Note 1 to paragraph (g) of this AD: CMR task number 612000-109, Operational Check of the Propeller Overspeed Governor, in Bombardier Q400 Dash 8 Temporary Revision (TR) ALI-129, dated September 3, 2013, is an additional source of guidance for the operational check of the propeller overspeed governor specified in paragraph (g) of this AD.
