What was found
WEATHER RADAR DOES NOT WORK PROPERLY IN AUTO. OVER FLAT TERRAIN, CLEAR SKY, IN WX+T MODE, SCREEN MOSTLY RED & YELLOW WITH AREAS OF RED DOTS. WITH MANUAL TILT, RADAR MORE REALISTIC. WORKS FINE IN MANUAL MODE. AFTER APPROX 2 HRS, AT CRUISE WITH RADAR ON, CLUTTER WENT AWAY AND RADAR BEGAN TO WORK NORMAL IN BOTH AUTO & MANUAL MODES. GROUNDED - YES. AUTOTILT / MULTISCAN INOP. VERIFIED DEFECT, MANUAL TILT FUNCTION OPS NORMAL, AUTO TILT INOP. REMOVED AND REPLACED ANTENNA DRIVE UNIT REF AMM 34-43-11, GROUND VERIFICATION TEST PASSED.