A helicopter can survive a complete engine out at any point during appropriately chosen flight regimes: https://en.m.wikipedia.org/wiki/Helicopter_height%E2%80%

A helicopter can survive a complete engine out at any point during appropriately chosen flight regimes: https://en.m.wikipedia.org/wiki/Helicopter_height%E2%80%93velocity_diagram https://en.m.wikipedia.org/wiki/Helicopter_height%E2%80%93ve... In my layman understanding: the heuristic amounts to - at low altitudes you flare and cushion, and at high altitudes you enter autorotation.