040818-F-0703J-001 (Aug. 18, 2004)US Air Force (USAF) CAPT. Tom Yeager, Pilot, 492nd Fighter Squadron (FS), Royal Air Force (RAF) Lakenheath, United Kingdom (GBR), performs pre-flight check on his HA/LP-PPB Oxygen mask onboard a USAF F-15E Strike Eagle fighter during the Excalibur exercise. The Excalibur exercise is a bombing and gunnery competition that provides an opportunity for the United States and partner countries to learn to fly and fight together. It also promotes esprit de corps between US Air Force in Europe (USAFE) and RAF aircrews as they focus on basic surface attack missions. U.S. Air Force PHOTO by AIRMAN Basic Stacey Jeanpaul (RELEASED)