Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Raytheon (Beech) Model 400, 400A, 400T, and MU-300-10 airplanes, and Mitsubishi Model MU-300 airplanes, that currently requires a revision to the Airplane Flight Manual (AFM) to provide pilots with special operating procedures during icing conditions. This proposal would require modification of the horizontal stabilizer ice protection system. This proposal also would remove Model MU-300 airplanes from the applicability of that AD. This proposal is prompted by the development of a modification that will positively address the unsafe condition. The actions specified by the proposed AD are intended to prevent uncommanded nose-down pitch at certain flap settings during icing conditions.