Abstract: An emergency supply unit is provided with a ram-air turbine surrounded substantially concentrically by a casing forming a flow channel and driven by an air stream; an energy converter, driven by means of the ram-air turbine directly coupled via a drive shaft, for at least partly maintaining the functioning of a hydraulic system and/or electrical system on board an aircraft in an emergency situation; means for installing the ram-air turbine in its position within the casing such that the spatial position of the ram-air turbine remains unchanged when the emergency supply unit is selectively brought into a standby mode or into an operating mode; at least one air inlet through which the air stream can be delivered to the ram-air turbine, and which is adapted to be closed by a shut-off member; and an air outlet adapted to be closed by a shut-off member.

Abstract: The invention relates to an emergency supply unit (1) with a ram-air turbine (2) which can be driven by an air stream (14) and with an energy converter (4) for at least partly maintaining the functioning of a hydraulic system and/or electrical system on board an aircraft in an emergency situation, wherein the energy converter (4) can be driven by means of the ram-air turbine (2) and the emergency supply unit (1) can selectively be brought into a standby mode or into an operating mode. According to the invention, at least the ram-air turbine (2) is surrounded substantially concentrically by a casing (5) forming a flow channel (6) and the energy converter (4) is directly coupled to the ram-air turbine (2) via a drive shaft (3) and the air stream (14) can be delivered to the ram-air turbine (2) through at least one air inlet (9, 17, 18), wherein the spatial position of the ram-air turbine (2) remains substantially unchanged when changing between the standby mode and the operating mode.