U.S. Marine Corps Lance Cpl. Jeremiah Calvert, a mechanic with Marine Medium Tiltrotor Squadron (VMM) 268, Marine Aircraft Group 16, 3rd Marine Aircraft Wing (MAW) replaces an engine air particle separator door actuator on an MV-22B Osprey aircraft at Eastern Sierra Regional Airport in Bishop, Calif., during Mountain Exercise (MTNEX) 1-15, Feb. 2, 2015. VMM-268 participated in MTNEX 1-15 in support of 2nd Battalion, 6th Marine Regiment, 2nd Marine Division, with Assault Support operations in a dynamic high altitude training environment. (U.S. Marine Corps photo by Cpl. Allison J. Herman, 3rd MAW Combat Camera/Released)