As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 5177 - UPON CLIMBING THE PILOTS REPORTED THAT THE APU BLEED WOULD NOT MAINTAIN GREATER THAN 3.5 PSI WITH PACKS IN LOW OR NORM. ENGINE BLEEDS WERE SELECTED TO AUTO & PACKS LOW AND THE AIRCRAFT COULD ONLY MAINTAIN 4.0 P.S.I. PACKS SELECTED TO NORM ACHIVED 4.5 P.S.I. THEN IT STARTED TO CLIMB. MX PLACED THE ISSUE ON MEL 21-31-1-3 CAT.C C/N 34027. ALL MX PROCEDURES C/W AND PLACARD INSTALLED.