Authorities identified a U.S. Marine from California as one of four people killed when a small plane contracted by the U.S. military crashed in the southern Philippines. Sgt. Jacob M. Durham, 22, of Long Beach, California, died Thursday, Feb. 6, when the aircraft went down in a rice field near Ampatuan, a town in Maguindanao del Sur province. Three defense contractors were also killed. What was the purpose of the flight? The plane was conducting a routine intelligence, surveillance and reconnaissance (ISR) mission at the request of the Philippine military, according to officials at Camp Pendleton in California. The U.S.…