Airworthiness Directives; Cessna Model 560 Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Cessna Model 560 airplanes. This AD requires installing new minimum airspeed placards to notify the flightcrew of the proper airspeeds for operating in both normal and icing conditions. This AD also requires revising the airplane flight manual to provide limitations and procedures for operating in icing conditions, for operating with anti-ice systems selected "on" independent of icing conditions, and for recognizing and recovering from inadvertent stall. This AD also provides an optional terminating action for the placard installation. This AD results from an evaluation of in-service airplanes following an accident. The evaluation indicated that some airplanes may have an improperly adjusted stall warning system. We are issuing this AD to prevent an inadvertent stall due to the inadequate stall warning margin provided by an improperly adjusted stall warning system, which could result in loss of controllability of the airplane.