What was found
FOLLOW-UP TO RECENT HISTORY OF DUCT PRESSURE SPLIT WITH RT PRESSURE LOW. ACFT GROUNDED. WHILE ACCOMPLISHING NR 2 ENGINE BLEED AIR SYS HEALTH CHECK, TASK CARD NG-36WC-00001, FOUND PRE-COOLER CONTROL VALVE FAILED STEP F AND HIGH STAGE VALVE FAILED IAW STEPS J AND K. R & R NR 2 ENGINE PRE-COOLER CONTROL VALVE REF AMM 36-12-02. INSTALLATION TEST OK. NO LEAKS NOTED. R & R NR 2 ENGINE HIGH STAGE VALVE REF AMM 36-11-06. INSTALLATION TEST OK. NO LEAKS NOTED. ACCOMPLISHED ENGINE BLEED AIR CROSSOVER TEST IAW MM 36-11-00. TEST GOOD.