A 22-year-old airman from Travis Air Force Base was sentenced to 14 years in federal prison at his military court martial in connection with the June shooting death of a fellow airman. Sgt. Sandra Whipps said Airman First Class Richard Emmons of Plainsfield, Vt., pleaded guilty to carrying a concealed weapon and the use of cocaine. He also was found guilty of aggravated assault in the June 21 shooting death of Douglas Lawrence, 21, of Gentana, Mont., a senior airman. Whipps said Emmons, Lawrence and a third airman who was not involved in the incident, were driving back to the Fairfield base from Vacaville when Lawrence was shot in the head. The car skidded off the road and hit a tree stump. At first, Emmons insisted that it was a suicide, Whipps said. Later, he confessed that he had shot Lawrence accidentally.