Refueling Window Staff Sgt. Bryan Groshek, a boom operator with the Wisconsin Air National Guard, refuels an F-15 Eagle during Sentry Aloha 19-1, Dec. 13, 2018. Sentry Aloha is a large-scale fighter exercise. SHARE: Download: Full Size (0.7 MB) Tags: Air Force, National Guard Credit: Tech. Sgt. Heather Redman VIRIN: 181213-F-ZT243-0193.JPG Photo Gallery