Induced drag or lift-dependent drag or lift induced drag is the drag which is created or “induced” as an inevitable consequence of generating lift.

As altitude increases and the air becomes less dense, more lift is required to support the helicopter's weight. Thus, the induced drag increases as altitude increases or air density decreases.

Engine power is required to overcome the induced drag on the rotors. Generally, it states that the Power required is: Drag x TAS.

Since, the induced drag increases with altitude, if multiplied by TAS, the corresponding Power, the Induced Power, will also increase as altitude increases.

Maximum range speed is normally referenced to IAS in the Helicopter Flight Manual. For a given IAS, as altitude increases, then the same airspeed as a TAS increases.