As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PIT-MDT - FLT 710 - AFTER TAKEOFF THE PRESSURE WENT TO ZERO FOR THE LEFT ENGINE HYDRAULIC PUMP. FOR MAINTENANCE CONVENIENCE THE AIRCRAFT RETURNED TO THE FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LEFT ENGINE DRIVEN HYDRAULIC PUMP. (M)