What was found
UPON ROLLING ONTO THE RUNWAY FOR TAKEOFF, "RA1 FAIL" WAS ANNUNCIATION ON THE ED. TAKEOFF ABORTED. REMOVED FROM SERVICE. SYSTEM PLACED ON MEL. CLEARED BY PERFORMING Q400 FIM 34-44-00-810-809. NO PRESENT FAULTS, PERFORMED RA1 TRANSCEIVER OPS TEST REF Q400 MTC 6344401. OPS TEST GOOD, NO FAULTS OR DEFECTS NOTED. A/C IS CAT III, COCKPIT PLACARD READS CAT III, MTX CTRL 46053 NOTIFIED, CLEAR MEL, PLACAREDS REMOVED, C/B PUSHED IN. RETURNED TO SERVICE. COULD NOT DUPLICATE. NO PARTS REPLACED.