The U.S. Air Force is still looking for aircraft to replace over 500
aging ( 40 years old, or older) KC-135 tankers. At the moment, there are three
prime candidates. The leading one is the KC-767, which is already been selected
by Italy and Japan. This aircraft is based on the Boeing 767-200 airliner,
which sells for about $120 million. Boeing developed the KC-767, at a cost of
nearly a billion dollars, on its own. Boeing also developed the original KC-135
tanker in the 1950s. All 732 KC-135s were built between 1956 and 1965.
the decades, the KC-135 fleet has undergone constant repair and reconstruction.
New engines, and new structural components have been added, as older items wore
out, or showed signs of wearing out. Currently, some 40 percent of the KC-135s
are out of action for maintenance problems. In theory, an aircraft can be
continually rebuilt and kept in flying condition. But the air force, and some
commercial air lines, are finding that the maintenance problems multiply and
become unpredictable as the aircraft get older and, after a while, the downtime
for maintenance is more trouble than it's worth. For example, the hundred
oldest KC-135s spend an average of 80 days a year undergoing major repairs.
However, when you do the math, you find that overhauling and maintaining the
current KC-135 fleet would be about $10 billion cheaper than buying new
767s. There is risk in keeping 40 year old aircraft flying, but the
safety record of the KC-135 remains excellent. Newer isn't always better, but
it is often more expensive.
four engine KC-135 carries 90 tons of fuel and can transfer up to 68 tons.
Consider that a B-52 carries over 140 tons of jet fuel, an F-15, over five
tons. A KC-767 carries about as much fuel as the KC-135. The European firm
Airbus, is offering the KC-30, based on the Airbus 330-300, which normally
sells for $160 million each. The KC-30 carries 20 percent more fuel than the
KC-767, and more cargo pallets (26 versus 19).
KC-135 has long made itself useful carrying cargo and passengers, as well as
fuel, and both the KC-767 and KC-30 have more capacity for this. Another option
is a tanker based on the larger Boeing 777-200LR, which sells for about $230
million each. This KC-777 would have 65 percent more fuel capacity than the
KC-767, and 95 percent more cargo capacity. Bigger is sometimes better if
you're a flying gas station. The KC-767 was developed partly because it is
about the same size as the KC-135 (wingspan is 156 feet, ten more than the
KC-135). The wingspan of the KC-777 would be 213 feet. Moreover, it would take
about three years to develop the KC-777, while the KC-767 is ready to go now,
and the KC-30 will enter service with Australia next year. Using the KC-777
would reduce the number of tankers needed from 179 to 120, or less, and be
cheaper in the long run. So many choices, and no one in authority is, as yet,
willing to make a decision on this.