Airworthiness Directives; Bombardier Model DHC-8-400, -401, and -402 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-400, -401, and -402 series airplanes. This action requires revising the Airplane Flight Manual to advise the flight crew of appropriate procedures to follow in the event that a main landing gear (MLG) fails to extend following a gear-down selection. This action also requires replacement of the left and right MLG uplock assemblies with new assemblies; and an inspection of the left and right MLG uplock rollers for the presence of an inner low friction liner, and corrective actions if necessary. This action is necessary to ensure that the flight crew has the procedures necessary to address failure of an MLG to extend following a gear-down selection; and to detect and correct such failure, which could result in a gear-up landing and possible injury to passengers and crew.