What was found
FLIGHT 3879, CREW REPORTED SHORTLY AFTER TAKE OFF, CAPTAIN`S AHARS WAS LOST THEN CAME BACK. ALL THREE HEADING INDICATIONS WERE OFF BY 30-40 DEGREES, THEN FIRST OFFICER’S AHARS WAS LOST UNTIL DOWNWIND INTO DESTINATION. DECLARED AN EMERGENCY AND RETURNED. AIRCRAFT LANDED WITHOUT INCIDENT AND REMOVED FROM SERVICE. REMOVED AND REPLACED NR 1 AND NR 2 ATTITUDE HEADING COMPUTERS IAW AMM 34-21-01. OPS CHECKED GOOD REF NRWCS 546O-ORD-00425 AND 546-ORD-00426. AIRCRAFT OK FOR SERVICE.