The debate among users continues with this issue. Some pilots and passengers have always believed two is better than one. On certain levels this is still true today. Anyone flying 100 miles offshore, or over mountainous terrain at night feels better knowing that there are two engines working for him or her. However, with the advent of truly reliable turbine engines, the probability of and engine failure is greatly reduced making the single-engine helicopter a safe and economical choice. A great deal depends on the type of missions flown, and the space required to accomplish it. All medium and large capacity helicopters are multi-engine, needed for the power required to lift the payload.