Transport distances with patient, and estimated costs by system and distance. RA = road ambulance (n = 17); RW = rotor wing ambulance (n = 71); FW = fixed-wing ambulance (n = 68). Individual points on each line represent transport distances where there can have been many actual transports superimposed. Helicopter transport costs by distance and patient time are clearly more expensive than RA and FW systems. Different helicopter models and crew configurations lead to different operating costs over distance and transport mission, though RW costs are always more than double that of the other systems related to distance, though the relative time-effectiveness of helicopter missions reduces relative mission time for shorter transports (below 500 km), as shown in Figure 2. Since there were multiple transports over the same distances (between two hospitals), only the unique distances are noted on the regression lines. RW1 represents Eurocopter AS 365 N3 Dauphin, and RW2 represents Eurocopter AS 365 N2 Dauphin configurations.