Abstract: A power margin indicator for a rotary-wing aircraft, intended to give information on the power margin available on at least one engine and one gearbox of the aircraft. The indicator includes: (a) input unit (5) for the various control parameters of the engine and of the gearbox, (b) calculation device (6) connected to the input unit (5) which, on the basis of the parameters, formulate the power margin, expressed as a collective-pitch value, and (c) display units (4, 8, 9) showing, on a display screen (7), the power margins represented on a scale (8) which is graduated in collective-pitch equivalents, capable of moving past a pitch index (9) in a window (4) of the screen (7).

Abstract: This relates to a helicopter in which the outlet nozzle from the turbine engine is provided with an exhaust pipe which mixes the combustion gases with fresh air and directs the mixture downward. Viewed from the outside of the helicopter, the exhaust pipe is completely concealed by a cowling which is separated from said exhaust pipe by an empty intermediate space, air intakes being provided to create a flow of ambient air, including during hovering flight, along the intermediate space as far as an outlet which is open substantially vertically downward.