Retirement ceremony for Master Sgt. Troy Crowell Published Oct. 6, 2009 VANCE AIR FORCE BASE, Okla. -- Congratulations and good luck Master Sgt. Troy Crowell. Thank you for your service. Time in service: 20 years Retirement ceremony: At 4 p.m., Thursday, Oct. 8, in the 71st Operations Support Squadron auditorium, Bldg. 690. A reception will follow in the conference room