Coal: Berlin's Key to Survival By The single most critical necessity for Berlin to survive was fuel. Coal became the major cargo of U.S. Air Force C-54s and ultimately made up 65 percent of the total tonnage flown into Berlin. Coal was dirty, dusty and heavy, all of which created major problems for both aircraft and crew. Coal dust seeped into every part of the aircraft, causing damage that included corrosion of control cables and erosion of electrical connections. It caused equal problems for crews, who complained of breathing problems and headaches. The only way to effectively handle the coal, as a cargo, was to place it in bags. Many types of bags were tried, but finally one-half million army surplus duffel bags were found for this purpose. The average USAF C-54 carried 10 tons of bagged coal. The Airlift flew a total of 1.5 million tons of coal into Berlin. Click here to return to the Berlin Airlift Overview.