The Orange County Sheriff's Department's Air Support Unit flies out of the John Wayne Airport (SNA) in Santa Ana California, so it is appropriate that their two Eurocopter AS 350 helicopters go by the call signs "Duke I" and "Duke II" while on patrol.
The unit began operations in 1985 with two MD500E helicopters but eventually transitioned to the MD600N (no tail rotor) helicopters in 1998. The MD600N was a faster and much quieter helicopter than the 500E. The Orange County Sheriff's Department was the first police agency in the country to place the MD600N into service as a police patrol helicopter. In 2005 the unit began their transition to the helicopters they operate today, two American Eurocopter AS 350B2 (Astar) helicopters.
The Aviation Support Unit is currently staffed with one Sergeant and eight Deputy Sheriff II's. All of which are are very experienced law enforcement officers with a wide range of aviation and law enforcement experience. The average Unit member is 46 years old and has 22 years of law enforcement experience. Each pilot holds a FAA Airline Transport Pilot or a Commercial Pilot's Certificate with a rotorcraft-helicopter rating and has an average flight time in excess of 7,000 hours.