What was found
REV 3 PRESS FAULT ON T/O REJECTED T/O AT 60KT. PERFORMED HI-POWER RUN IAW JRH, REV 3 PRESS FAULT APPEARED BEFORE 80 PERCENT. SUSPECT NR 3 PRESS REG SHUTOFF VALVE AT FAULT. SWAPPED NR1 AND NR3 PRESS REG SHUTOFF VALVE FOR T/S PURPOSE AND PERFORMED HI-POWER RUN IAW JRH. PROBLEM TRANSFERRED TO NR1. SWAPPED BACK TO ORIGINAL POSITION IAW MM78-31-07-4. NR1 AND NR3 TR OPS CHECK REQUIRE AFTER REPLACE NR3 PRESS REG SHUTOFF VALVE. ENGINES RAN BY 562898. REMOVED AND REPLACED NR 3 T/R PRESS REG S/O VALVE AND PERFORMED NR 1 & NR 3 T/R OPS C'K BY APU AIR IAW MM78-31-07-4. ALL TEST PASSED. RAN NR1 & NR 3 HI PWR ENG RUN IAW JRH. ALL INDICATION NML. CLOSE AND SECURED BOTH ENG COWL IAW MM 71-10-00-2. ACFT OK FOR SVC.