TRAVIS AIR FORCE BASE, Calif. (AP) – A motorist’s vehicle burst into flames after crashing at the main gate of a Northern California Air Force base in what investigators are calling a security incident. Travis Air Force Base officials and the FBI said Thursday that they are investigating Wednesday’s incident and that there are no current threats to the base. Both declined further comment. The incident occurred around 7 p.m. Wednesday when the driver “gained unauthorized access” to the main gate at an Air Force base about 55 miles northeast of San Francisco. Some 7,000 active military members and 3,700 civilians live and work on the base.