What was found
DURING FLIGHT, THE COPILOTS GPS LOST ALL OF ITS PRIMARY FLIGHT DATA AND DISPLAYED ALL RED X'S. THIS LASTED FOR JUST UNDER 2 MINUTES AND THEN RETURNED TO NORMAL ON ITS OWN. ON APPROACH, THE PILOTS GPS, AUDIO SELECTOR, AUTOPILOT, AND INVERTER ALL TRIPPED OFF LINE. CAPTAIN NOTICED THAT BOTH 50AMP NR 1 DUAL BUSS FEED BREAKERS WERE TRIPPED. THE LANDING WAS ABORTED AND PILOT CLIMBED BACK UP TO ALTITUDE. 7600 WAS THEN SELECTED ON THE TRANSPONDER AND THEY HEADED BACK TO ANC. CALLED THE TOWER AND DECLARED AND EMERGENCY. THE LANDING WAS UNEVENTFUL. OPEN.