Turn times really depend on the aircraft, the loading system, the delays at the field, etc. If there are no traffic delays and there's no one in the reartardant pilt, 15 to 20 minutes without refueling, but again, that depends on the aircraft. Piston airplanes needing fuel also often require oil, which takes extra time. Mechanical issues may take extra time. If nothing but retardant is needed, then it can go quickly with typical high pressure systems.
Seats typically average about a five minute turn, and ground delays are generally minimal because more often than not the SEAT is using a rural, smaller airport.
Actual turn-arounds from the fire really depend on where the fire is in proximity to a reload base.
I see the Evergreen 747 got used for the first time on a fire on a revenue flight, yesterday.
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