Helicopters aren’t supposed to be able to accommodate ejector seats…so today’s invention is one such system.
A rotary-wing aircraft is equipped with an internal, sliding palette to which all the seats are attached within a boat-shaped tub (broadly similar to the way in which large packages or vehicles are air-dropped). This has a drogue parachute and a main chute attached to each end.
In an emergency, the drogue is fired backwards, extracting all personnel strapped into the gondola, supported by the two main chutes.
Even if only one main chute opens, a safe landing can be made (at sea, buoyancy bags would be automatically inflated).