A short but spectacular video of a DC-10-10 air tanker dropping fire fighting retardant. The aircraft are operated by US company 10 Tanker. The company has had three DC-10s converted to date, two of which are in service. Each carries nearly 12,000 US gallons (45,000 litres) of water or fire retardant in an exterior belly-mounted tank, the contents of which can be released in eight seconds.
UPDATE 24 September 2014: An illustration of the dangers of aerial fire fighting can be found in this NTSB report issued today.
UPDATE 18 November 2014:FireAviation report that the first DC-10 to be converted for 10 Tanker has been retired, after 10 years service and 1,250 missions. The company is converting a fourth DC-10 which will take on the same fire fighting callsign ‘Tanker 910’.