A C-5 Galaxy approaches the boom of a KC-10A Extender with the 163rd Air Refueling Wing from March ARB, California, to begin refueling operation during Exercise Red Flag 99-1 at Nellis AFB, Nevada. Red Flag is a simulated training exercise held by the US and its allies. It is conducted on the vast range north of Nellis AFB. Red Flag is one of a series of advanced training programs administered by the 414th Combat Training Squadron, Air Warfare Center at Nellis AFB