U.S. Marine Corps Sgt. Ryan Boele reinstalls a prop rotor hub on an MV-22B Osprey aircraft during Mountain Exercise 6-15 at Mountain West Aviation, South Lake Tahoe, Calif., Oct. 26, 2015. Boele is a mechanic assigned to Marine Medium Tiltrotor Squadron 163, Marine Aircraft Group 16, 3rd Marine Aircraft Wing. U.S. Marine Corps photo by Cpl. Allison J. Herman