Airworthiness Directives; Bombardier Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-102, -103, -106, -201, - 202, -301, -311, and -315 airplanes. This AD requires modification of the No. 3 electrical equipment panel behind the avionics rack, and modification of the No. 2 propeller de-ice timer. This action is necessary to prevent incorrect altitude information transmitted by the Mode S transponder and simultaneous loss of the Traffic Alert and Collision Avoidance System (TCAS), and increasing the possibility of an air traffic conflict. This action is intended to address the identified unsafe condition.