As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 4171 - CREW REPORTED AN AIRFRAME/AIRBLEED FAULT FOLLOWED BY A HYDRAULIC LOW PRESSURE AND AN ACRIC SMELL IN THE COCKPIT. RAI'D AIRFRAME AIRBLEED PRESSURE SWITCH AND RESET CB FOR HYD SYSTEM. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE. (M)