Water survival refresher trainee, Master Sgt. Joshua Mal, 3rd Airlift Squadron C-17A Globemaster III loadmaster, keeps his head above water under the supervision of Staff Sgt. Adam Ellerd, 436th Operations Support Squadron Survival, Evasion, Resistance and Escape Operations NCO in charge on Friday, July 17, 2015, near Dover Air Force Base, Del. Mal and other students had to find and release their torso harness fittings while being towed through the water to simulate being dragged by their canopy after landing in water. (Greg L. Davis/U.S. Air Force)

A security forces airman plunges into the water as part of a survival test at the U.S. Air Force Academy, Colo., on Friday, July 17, 2015. The event was part of a one-day course for airmen to determine if fitness to attend the U.S. Army Pre-Ranger Training Assessment Course. (Jason Gutierrez/U.S. Air Force)

An airman from the 5th Civil Engineer Squadron hangs upside down during rappelling training at Minot Air Force Base, N.D., on Sunday, July 9, 2015. Repelling was a portion of a rope-rescue class provided to airmen to prepare them to descend down the side of buildings or enter confined spaces. (Sahara L. Fale/U.S. Air Force)

A UH-N1 Iroquois circles during a search-and-rescue training mission near Garrison, N.D., on Monday July 20, 2015. The crew practiced search-and-rescue operations in preparation for the upcoming Air Force Global Strike Command's Global Strike Challenge. (Stephanie Morris/U.S. Air Force)

U.S. and Bulgarian paratroopers jump from a C-130J Super Hercules during a high-altitude, low-opening jump over Plovdiv, Bulgaria, on Tuesday, July 14, 2015. (Nicole Sikorski/U.S. Air Force)

Tech. Sgt. Shawn Rankins and military working dog, Eespn, 82nd Security Forces Squadron, demonstrate aggression training on Tuesday, Aug. 4, 2015, at Sheppard Air Force Base, Texas. (Danny Webb/U.S. Air Force)

U.S. Air Force Senior Airman Charles Ballou, 823rd Expeditionary RED HORSE Squadron pavements and construction equipment operator, plays with local children near the well site in Brisas del Mar, Honduras, on Monday, Aug. 3, 2015. (David J. Murphy/U.S. Air Force)