Airworthiness Directives; Hawker Beechcraft Corporation (Type Certificate Previously Held by Raytheon Aircraft Company; Beech Aircraft Corporation) Model 400A and 400T Airplanes

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires a detailed inspection for proper sealant of the left and right pylon firewall structures, and corrective actions if necessary. This AD results from reports of missing sealant on the left and right pylon firewall structures. We are issuing this AD to detect and correct missing sealant on the left and right pylon firewall structures, which, in the event of an engine fire, could result in flames penetrating the seams in the firewall between the engine and the aft fuselage, and a subsequent uncontrolled fire in the aft fuselage.