What was found
RIGHT BLEED DUCT OSCILLATES B-W 20-40 PSI DURING CLIMB. IN DESCENT RT DUCT 20 PSI LESS THAN LEFT. VALVE IN LOCKED INTERMEDIATE POSITION. FAULTING FAN AIR TEMP SENSOR. ON TAKEOFF AND CLIMBOUT RIGHT DUCT PRESSURE RAPIDLY FLUCTUATED BETWEEN 20 AND 40 PSI, PER CREW REPORT. ACCOMPLISHED PNEUMATIC HEALTH CHECK ON PRSOV REF AMM, PRSOV FAILED TEST. REPLACED PRSO VALVE. ACCOMPLISHED LEAK CHECK OF VALVE AND ACCOMPLISHED RUN, STILL FLUCTUATES. UPDATE SHOULD READ ONLY THE HIGH STAGE IS FLUCTUATING. BLEED SHIFT IS GOOD. HP BLEED VALVE MADE INOPERATIVE.