As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - SYSTEM ONE HYDRAULIC LOW PRESS CAUTION LIGHT CAME ON AND NUMBER ONE HYDRAULIC SYSTEM QUANTITY SHOWS ZERO IN FLIGHT. CREW PERFORMED EMERGENCY/ABNORMAL CHECKLIST. FOUND LEFT ENGINE DRIVEN HYDRAULIC PUMP LEAKING. REPLACED THE NUMBER ONE HYDRAULIC PUMP. OPERATIONAL CHECK AND LEAK CHECK IS GOOD. AIRCRAFT RETURNED TO SERVICE.