What was found
TAKEOFF WARNING HORN SOUNDED DURING TAKE OFF ROLL, RESULTING IN AN ABORT AT 50-55 KTS. WIRING SYSTEM HAD TESTED OK DURING TAKEOFF CHECK LIST. AFTER ABORT, ETA CHECK LIST ITEMS ALL AS SHOULD BE, PARK BRAKE OFF, CONDITION LEVERS MAX, FLAPS 5 DEG & ELEVATOR TRIM IN MIDDLE OF TAKE OFF RANGE. CONDUCTED ELEVATOR TRIM TEST IAW ETA, CONDUCTED SUCCESSFUL TAKEOFF WIRING TEST. ADVISED BY MAINT TO RTG. COMPLIED WITH FUNCTIONAL TEST OF THE TAKE-OFF WARNING SYS IAW AMM 31-52-00-720-801. NO DEFECTS NOTED. OK FOR CONTINUED SERVICE. NO PARTS REPLACED.