A power plant (2) having at least one engine (3, 4) and control means (5) for controlling said engine (3, 4). The control means (5) include a memory (6), said memory (6) containing information for operating said engine (3, 4) in accordance with at least two distinct utilization envelopes during a maximum number of flying hours, the two envelopes comprising an envelope enabling takeoff from a platform and another envelope enabling takeoff from takeoff zones not including platforms, each utilization envelope comprising at least two distinct utilization ratings each defined by a developed power and by a utilization duration for said developed power.