151026-M-DF987-210 SOUTH LAKE TAHOE, Calif. (Oct. 26, 2015) U.S. Marine Corps Sgt. Ryan Boele, a mechanic from Marine Medium Tiltrotor Squadron (VMM) 163, Marine Aircraft Group 16, 3d Marine Aircraft Wing (3d MAW), reinstalls a prop rotor hub on an MV-22B Osprey aircraft during Mountain Exercise (MTNEX) 6-15 at Mountain West Aviation, South Lake Tahoe, Calif., Oct. 26, 2015. VMM-163 participated in MTNEX 6-15 to develop the squadron's expeditionary proficiency in a dynamic high altitude, cold weather training environment. (U.S. Marine Corps photo by Cpl. Allison J. Herman/Released)