Abstract: An Environmental Control System (ECS) which includes a heat exchanger (HX) and an air conditioning unit (ACU) upstream of the heat exchanger. The heat exchanger receives flows of hot air bled from a plurality of aircraft engines and flows of cold ambient air drawn from the aircraft exterior for use by the heat exchanger and the air conditioning unit for heating and cooling the interior cabin of the aircraft. The environmental control system may operate in one of several modes, whether the heat exchanger and air conditioning unit are operating normally or have failed. In a normal mode, the air conditioning unit and heat exchanger operate in series. In an “ACU only” mode, the air conditioning unit operates without the heat exchanger. In an “HX only” mode, the heat exchanger operates without the air conditioning unit. In an “ECS off” mode, both the heat exchanger and air conditioning unit are bypassed.

Abstract: An Environmental Control System (ECS) for aircraft is provided. The ECS includes a heat exchanger (HX) and an air conditioning unit (ACU) upstream of the heat exchanger. The heat exchanger receives flows of hot air bled from a plurality of aircraft engines and flows of cold ambient air drawn from the aircraft exterior for use by the heat exchanger and ACU for heating and cooling the interior cabin of the aircraft. The ECS may operate in one of several modes, whether the heat exchanger and air conditioning unit are operating normally or have failed. In a normal mode, the ACU and heat exchanger operate in series. In an “ACU only” mode, the ACU operates without the heat exchanger. In an “HX only” mode, the heat exchanger operates without the ACU. In an “ECS off” mode, both the heat exchanger and ACU are bypassed.

Abstract: A main rotor support structure assembly includes a support housing which transmits loads developed by the main rotor assembly into the airframe. Integral main rotor servo attachment lugs extend from the cylindrical body member to provide lower attachment points for the rotor servo actuators which are operable to articulate a rotor swash plate or the like. The servo attachment lugs are integrally formed as part of the cylindrical body member and spaced thereabout. A substantially L-shaped metallic insert is sandwiched and bonded within each servo attachment lug to resist axial and transverse tension of the rather high forces exerted by the rotor servo actuators.