What was found
DURING CLIMB FL 390 100% N1, LEFT DUCT PRESSURE 22PSI, RIGHT DUCT PRESSURE 42 PSI. ACFT GROUNDED. CHECKED AND RELEASED IAW FIM TASK 36-10/811, FOR A PERIOD OF 10 DAYS. FOUND TO BE WITHIN LIMITS. ACCOMPLISHED NR 1 ENGINE BLEED AIR SYSTEM HEALTH CHECK IAW TASK CARD NG-36WC-00001. FOUND PRSOV AND PRECOOLER VALVE FAILED DURING THE TEST. REPLACED PRSOV IAW AMM 36-11-04-400-801, LEAK AND OPS CHECKED GOOD. REPLACED PRE COOLER VALVE IAW AMM 36-12-02-400-801, LEAK AND OPS CHECKED GOOD. ACCOMPLISHED ENG BLEED AIR CROSSOVER TEST, TEST FAILED. REPLACED BLEED AIR REGULATOR IAW AMM 36-11-03-400-801, LEAK AND OPS CHECKED GOOD. PERFORMED ENG BLEED AIR CROSSOVER OPERATIONAL TEST AGAIN, TEST PASSED.