Flight Crew Air Transport Pilot (ATP)
Ground Event / Encounter Loss Of Aircraft Control
Flight Crew Regained Aircraft Control; General Flight Cancelled / Delayed
Procedure; Airport; Weather
NOTAMs described all taxi surfaces as poor braking. The runway was 4/4/4 with 25% ice. When taxing out of the Rochester ramp; after crossing Runway 28 on Taxiway F; we got into an area of nil braking and the aircraft skidded for about 50 feet. I was only taxing about 3 mph so I stopped the aircraft and called for a tug. The county came and spread sand over the bad areas and the tug subsequently pulled us to the departure end of the takeoff runway and the rest of the flight was uneventful.With rapidly changing weather conditions; the county should err on the conservative side and call the braking action Nil if there is any doubt. As I was listening to ground control prior to taxi; I heard a commuter airline call the airline ramp nil for taxi. This gave me an early indication of possible rapidly changing conditions.
Air carrier Captain reported skidding 50 feet on ice on Taxiway F past Runway 28 at ROC. The aircraft was subsequently towed to the runway for a normal departure.