GRAND FORKS AIR FORCE BASE, N.D. -- Master Sgt. Charles Breder, 319th Civil Engineers Squadron, and his crew use Dynamic Cone Pintrometer to measure the density of a filled in hole during thier exercise to train for Silver Flag in Fargo, N.D., August 30, 2007. The Squadron was tested on its war time mission and its abilitiy to adapt to unpredictable scenarios such as Rapid Runway Repair in Mission Oriented Protective Posture 4. (photo/Airman 1st Class Chad Kellum)