Corrosion problems in U.S. military aircraft
These tanker aircraft, known as KC-135s, are more than fifty years old and the cost of maintenance over the next eight years will rise to $6 billion annually, as corrosion attacks the metal cover and internal structure of aircraft.
The U.S. Department of Defense now has two bids to fully replace the KC-135 fleet by Boeing, the largest U.S. aircraft manufacturer, and the European Defense Aeronautics Company, which owns Airbus, the continent's largest aircraft manufacturer.
However, even if the purchase contract is defined before the end of the year, the KC-135s will have to continue flying indefinitely, while the aircraft are built and put into operation.