However, many (probably all, but I don't know for sure) heavy lift or rescue helicopters are multi-engine. For example, the Westland Sea King (Powerplant: 2 × Rolls-Royce Gnome H1400-2 turboshafts, 1,660 shp (1,238 kW) each)[1] or a newer Sikorsky S-92 (Powerplant: 2 × General Electric CT7-8A turboshaft, 2,520 shp (1,879 kW) each).[2]
Here's a document from the Civil Aviation Safety Authority (CASA) in Australia, concerning performance standards for multi-engine helicopters. It provides a pretty good overview of what they need to be able to do with one engine inoperative (OEI).[2]
