Abstract: A rotary wing aircraft with a fuselage that forms an aircraft interior region, the fuselage comprising an upper primary skin that separates the aircraft interior region from an aircraft upper deck arranged above the fuselage, the upper primary skin being mounted on top of a predetermined number of supporting beams; wherein the aircraft upper deck comprises an engine accommodating region with a firewall arrangement, the engine accommodating region accommodating at least one aircraft engine within the firewall arrangement such that the firewall arrangement defines a fire proof separation at least between the at least one aircraft engine and the aircraft interior region; and wherein the firewall arrangement comprises at least a funnel-shaped lower firewall arranged between the at least one aircraft engine and the upper primary skin of the fuselage.

Abstract: A rotary wing aircraft comprising a fuselage tail boom, a tail cone and an interface frame, the interface frame in turn having a connecting structure directly attached to the tail cone by means of a tail cone mechanical connection and a connecting sleeve fitting axially the fuselage tail boom, the connecting sleeve and the fuselage tail boom being directly attached by means of a one boom mechanical connection; the interface frame thereby joining the fuselage tail boom and the tail cone.

Abstract: A rotary wing aircraft comprising a fuselage tail boom, a tail cone and an interface frame, the interface frame in turn having a connecting structure directly attached to the tail cone by means of a tail cone mechanical connection and a connecting sleeve fitting axially the fuselage tail boom, the connecting sleeve and the fuselage tail boom being directly attached by means of a one boom mechanical connection; the interface frame thereby joining the fuselage tail boom and the tail cone.