Port Alberni’s Coulson Aviation takes pride in designing and implementing the largest modification ever done to a Boeing 737.It has already converted six planes into air tankers for firefighting and is currently working on another one, a former Southwest Airlines 737-300 at its hangar at the Port Alberni Airport.“It gets the firefighting tank conversion and the whole airplane gets converted inside and out and so the conversion process from airliner to air tanker takes us about 60,000 man-hours,” said Britton Coulson. Coulson has also converted former US Army helicopters and its services are in demand around the world. …But the Vancouver Island company isn’t fighting any forest fires in B.C. or Canada and hasn’t for years. …“B.C. felt that we didn’t have the necessary experience to be able to fight fires in B.C. so we got kicked out of the bid [two years ago] even prior to evaluating the aircraft types or anything,” said Coulson.