What was found
ON DEPARTURE, FLIGHT DIRECTOR INOP BOTH SIDES AMBER A/P AND ATS BOXES IAS COMPARATOR BOTH SIDES. FA USING AIRSPEED LOST, SUSPECT ERROR. CHECKLIST DETERMINED. DETERMINED CADC NR 1 WAS AT FAULT. DIVERT TO ATL. FOUND FOD NR 1 PITOT TUBE. ALSO TUBE L/E ERODED. PURGED LINES FROM CADC NR 1 & 2 TO PITOT TUBES PER MM 34-11-0. LINES CLEAN, REPLACED NR 1 PITOT TUBE AND NR 1 CADC PRECAUTION PER 34-16-01. A/C RETURNED TO ATL.