Airworthiness Directives; Lockheed Model L-188A and L-188C Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to all Lockheed Model L-188A and L-188C series airplanes, that requires revising the Airplane Flight Manual to provide the flightcrew with modified procedures and limitations for operating in icing conditions. This amendment is prompted by incidents and accidents involving airplanes equipped with turboprop engines that experienced tailplane stall due to ice accretion on the horizontal stabilizer of the airplane. The actions specified by this AD are intended to prevent undetected accretion of ice on the horizontal stabilizer, which could result in ice contaminated tailplane stall and consequent loss of pitch control.