Airworthiness Directives; Raytheon Model DH.125, Model HS.125, Model BH.125, Model BAe.125 Series 800A (Including Major Variants C-29A and U1-25), Model Hawker 800, Model Hawker 800XP, and Model Hawker 1000 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Raytheon Model DH.125, Model HS.125, Model BH.125, Model BAe.125 Series 800A, Model Hawker 800, Model Hawker 800XP, and Model Hawker 1000 series airplanes, that requires leak checks and inspections for corrosion of the pitot/static and stall vent drain valves, and replacement of certain components, if necessary. This amendment is prompted by reports of plugged or taped drain valves as well as consequent corrosion of certain drain valves. The actions specified by this AD are intended to prevent erroneous altimeter and airspeed indications due to plugged or taped pitot/static and stall vent drain valves.