Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to certain McDonnell Douglas Models DC-3 and DC-4 series airplanes, that would have required revising the Airplane Flight Manual (AFM) to include requirements for activation of the airframe pneumatic deicing boots. That proposal was prompted by reports of inflight incidents and an accident that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. This new action revises the proposed rule by adding an inspection to determine the type of pneumatic deicing boots, and requiring the AFM change only for those airplanes equipped with ``modern'' boots. The actions specified by this new proposed AD are intended to ensure that flightcrews activate the pneumatic wing and tail deicing boots at the first signs of ice accumulation. This action will prevent reduced controllability of the aircraft due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle.