Airworthiness Directives; Dornier Model 328 Series Airplanes Equipped With Honeywell GP-300 Guidance and Display Controller

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Dornier Model 328 series airplanes, that currently requires modification of certain Honeywell GP-300 guidance and display controllers. That AD was prompted by reports of smoke and fumes emitting from the Honeywell GP-300 guidance and display controller due to a defective light bulb; and a report of failure of the autopilot to disconnect manually. The actions specified by this AD are intended to prevent a defective light bulb from causing a short circuit that emits smoke and fumes into the cockpit; or causing damage to the circuit cards and various components, which may lock the autopilot into the engaged mode. Locking of the autopilot into the engaged mode could lead to the inability of the pilot to disconnect the autopilot, which could result in reduced controllability of the airplane. This amendment requires verification of proper installation of the modification, and repair, if necessary.