U.S. Marines with Marine Medium Tiltrotor Squadron

U.S. Marines with Marine Medium Tiltrotor Squadron (VMM) 161, Marine Aircraft Group 16, 3rd Marine Aircraft Wing (Forward) conduct maintenance on an MV-22 Osprey at Camp Bastion, Helmand province, Afghanistan, Nov. 4, 2102. The Marines changed the prop rotor gear box during routine maintenance. (U.S. Marine Corps photo by Sgt. Keonaona C. Paulo/Released)