Royal Canadian Air Force construction engineers from 19th Wing, Construction Engineering Flight, Canadian Forces Base Comox, British Columbia, set up a connection for a reverse osmosis water purification unit during a Silver Flag exercise March 7, 2013, at Tyndall Air Force Base, Fla. The Canadians trained side-by-side with U.S. Airmen during a week-long course designed to help them prepare to establish, sustain and recover an airfield in a contingency environment. (U.S. Air Force photo/Eddie Green)