As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT, THE 'B' SYSTEM LOW PRESSURE LIGHT ILLUMINATED FOLLOWED BY PRESSURE FLUCTUATIONS. 'B' SYSTEM QUANTITY DROPPED TO ZERO. CREW PERFORMED COM PROCEDURE AND LANDED WITHOUT INCIDENT. DTW MAINTENANCE REPLACED DEFECTIVE FLEX LINE RUNNING FROM RESERVOIR TO PUMP. ALL LEAK AND OPERAITONAL CHECKS GOOD.