What was found
DUCT PRESS WENT TO BELOW 5 AFTER TAKEOFF NO LIGHTS ILLUMINATED . (30 SPLIT) IN THE CLIMB L & R DUCT PRESSURES REDUCED TO A 25 PSI SPLIT. LEFT AT 35 PSI AND RIGHT AT 10 PSI. ALL ENGINE PARAMETERS NORMAL. GROUNDED - YES. REFERENCE W/O 1969977 T/C NG-36-WC-00001 FOR BLEED AIR HEALTH CHECK. NO DEFECTS NOTED. ACCOMPLISHED ENGINE BLEED AIR CROSSOVER OPERATIONAL TEST PER AMM 36-11-00-710-801. TEST PASSED. DUCT PRESSURES WITHIN LIMITS. LEAK CHECK GOOD.