As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX FLIGHT NR 2162, NR 1 STANDBY HYDRAULIC PRESSURE READS ZERO PSI WITH PROPS OUT OF FEATHER AND BOTH SWITCHES AT 1 AND 2. MAINTENANCE FOUND CIRCUIT BREAKER 29218 IN RIGHT WHEEL WELL OPEN, INSPECTED NR 1 STANDBY PUMP FOR OBVIOUS DEFECTS, NONE NOTED. RESET CIRCUIT BREAKER 29218 (REF HORIZON AIR GMM 5-18-0) COMPLIED WITH GROUND RUN AND CYCLED NR 1 HYDRAULIC SYSTEMS USING NR 1 STANDBY PUMP. OPERATIONAL CHECK GOOD. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.