High Quality Content by WIKIPEDIA articles! Air Test and Evaluation Squadron TWO THREE (VX-23) is a U.S. Navy Air Test and Evaluation Squadron based at Naval Air Station Patuxent River. Known by the nickname of the Salty Dogs, their tail code is SD, and they fly numerous USN aircraft.VX-23 is an Aircraft Test Squadron that conducts research, testing and evaluation of fixed wing tactical aircraft and UAV's. VX-23 provides aircraft, pilots, maintenance services, safety oversights and facility support for these operations.