Section 108.653 - Helicopter facilities(a) Each helicopter fueling facility must be marked adjacent to the fueling hose storage: "WARNING-HELICOPTER FUELING STATION-KEEP LIGHTS AND FIRE AWAY".(b) Each storage tank for helicopter fuel must be marked: "DANGER-FLAMMABLE LIQUID".(c) Each access to a helicopter landing area must be marked: "BEWARE OF TAIL ROTOR".(d) Each marking required by this section must be in letters at least 7.5 centimeters (3 inches) high.