A turboprop-powered medium altitude long endurance aircraft, having a gas turbine engine; a heat scavenging device to scavenge heat from the gas turbine engine; and a heating device to use the scavenged heat to provide heating to the aircraft. The heat scavenging device may be placed on an engine casing and/or on or in an engine exhaust duct. The heating device may include a circulation path routed directly to a location in the aircraft where heating is to be performed, for example a leading edge of an engine support pylon or a leading edge of an engine-carrying wing. The heating device can include a heat exchanger.