What was found
DURING TEST FLIGHT AT 15,500' AND 180 KTS, SLAT HANDLE MOVED TO EXTEND POSITION, SLATS WOULD NOT EXTEND. HANDLE MOVED BACK TO RETRACT & EXTEND AGAIN, SLATS FINALLY EXTENDED NORMALLY. HYD PAGE INDICATED NO QUANTITY,"HYD 3 FAIL" THEN DISPLAYED. COMPLIED W/RED TABS AND MADE UNEVENTFUL LANDING.