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U.S. Air Force 1st Lt. Andrew Johnson, a 20th Bomb Squadron navigator, conducts a preflight inspection on a B-52H Stratofortress aircraft during exercise Red Flag 13-2 at Nellis Air Force Base, Nev., Jan. 28, 2013.
Red Flag is an advanced aerial combat training exercise held four to six times a year to train pilots from the U.S., NATO and other allied countries for real combat situations. (U.S. Air Force photo by Senior Airman Matthew B. Fredericks). Original public domain image from Flickr
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