151026-M-DF987-203 SOUTH LAKE TAHOE, Calif. (Oct. 26, 2015) U.S. Marine Corps Sgt. Ryan Boele, left, and Cpl. Dillon Turner, mechanics from Marine Medium Tiltrotor Squadron (VMM) 163, Marine Aircraft Group 16, 3d Marine Aircraft Wing (3d MAW), reinstall a prop rotor hub on an MV-22B Osprey aircraft during Mountain Exercise (MTNEX) 6-15 at Mountain West Aviation, South Lake Tahoe, Calif. 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)