AF selects 3 at Sheppard detachments for promotion to E-8 Published March 5, 2009 82nd Training Wing Public Affairs SHEPPARD AIR FORCE BASE, Texas -- Three master sergeants at Sheppard detachments joined the other 12 selected locally to pin on senior master sergeant chevrons. Those selected include: Master Sgt. David Belcher, 366th Training Squadron, Fort Leonard Wood, Mo.; Master Sgt. Robert Corrigan, 381st TRS, Fort Sam Houston, Texas; and Master Sgt. Nick Grba, 373rd TRS, Tinker Air Force Base, Okla.