Firefighting bucket (11) suspended from an aircraft by lines (15), has open top (12A) and a valve at base (13). The valve is attachable to the aircraft by remotely actuatable line (16) and independent movement of lines (15-16) may utilize the weight of the water to facilitate opening and closing of the valve. Dynamic sensing of a bucket attribute, e.g. weight, enables bucket (11) to be filled or discharged by a pre-determined volume by the pilot. Chemical fire retardant may be added by entraining it with water discharging from the valve.