What was found
DUCT SPLIT DURING CLIMB PARAMETERS RECORDED AS FOLLOWS CLIMB THROUGH FL 270, L21 PSI, R 45 PSI, N1 99.9, N2 98.3, SAT-33C. CLIMB THROUGH FL 320, L22 PSI, R 46 PSI, N1 99.8, N2 97.5, SAT-44C. CLIMB THROUGH FL 340, L23 PSI, R 43 PSI, N1 100.3, N2 96.3, SAT -53C. LEVEL AT FL380, L23 PSI, R 38 PSI, N1 87.5, N2 91.0, SAT -56C. ACCOMPLISHED T/C NG-36WC-0001 -ENGINE BLEED AIR SYS. HEALTH CHECK. BLEED AIR REGULATOR FAILS HEALTH CHECK -PC IS ONLY 12 PSIG. PRECOOLER CONTROL VALVE FAILS TO FULLY OPEN AT 3PSIG. NO OTHER DEFECTS NOTED ON T/C. REPLACED NR 1 ENG BLEED AIR REGULATOR REF AMM 36-11-03-000-801. OPS AND LEAK CHECK GOOD. REPLACED NR 1 ENG PRECOOLER CONTROL VALVE REF AMM 36-12-02-000-801. OPS AND LEAK CHECK GOOD. OPS CHECK GOOD. ACCOMPLISHED ENG BLEED AIR CROSSOVER OPS TEST. OPS CHECK GOOD REF MM 36-11-00-710-801.