What was found
ON TAKEOFF WHEN SPEED WAS CHECKED AT 80 KNOTS, CAPTAIN AIRSPEED INDICATED 80 AND FO AIRSPEED INDICATED BETWEEN 40 AND 50. REJECTED TAKEOFF AND RETURNED TO RAMP. INSPECTED PITOT DRAIN IN NOSE WHEELWELL . NO WATER FOUND . INSPECTED LINES AT ADC 1 AND ADC 2 , NO WATER FOUND . INSPECTED F/O PITOT TUBE FOUND SIGN OF CRUSTY / CHARRED DEBRIS DEEP INSIDE PITOT TUBE (ABOUT 1 1/2 INCH FROM FRONT EDGE OF PITOT TUBE ). INSPECTED FO AND CAPT PITOT TUBES AND FLUSHED LINES FROM ADC1, ADC2. FO AND CAPT PITOT SYS LEAK CHECKS GOOD. FO AND CAPT AIRSPEEDS CHECK GOOD. VERIFIED BOTH SYS SPEEDS MATCHED AT 60KTS, 80KTS, UP TO 300KTS. NO LEAKS. AC OKAY FOR SERVICE.