Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This proposal would require 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.