A U.S. Navy helicopter crashed during a training mission in the Imperial County desert north of Yuma Thursday afternoon, the second military aircraft to go down in the area in two days, the Navy said. All four crew members on board survived the crash, although one sustained injuries not considered life-threatening and was taken to a hospital, according to Cmdr. Zachary Harrell, a spokesperson for the San Diego-based Naval Air Forces command. The MH-60S Seahawk helicopter is assigned to Helicopter Sea Combat Squadron 3, based at Naval Air Station North Island, Harrell said. The crash was reported around 5 p.m....