As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON LANDING GEAR RETRACTION ON CLIMB AFTER TAKEOFF, LANDING GEAR DID NOT RETRACT. THE LANDING GEAR POSITION INDICATORS REMAINED RED, AND THE HYD CAWS ILLUMINATED. THE PILOT NOTIFIED TOWER THEY WERE RETURNING TO THE FIELD THEN FOLLOWED THE APPROPRIATE CHECKLIST AND PLACED THE GEAR HANDLE IN THE DOWN POSITION. THE MLG LOCKED IN THE DOWN POSITION, THE NLG NEEDED TO BE PUMPED TO THE DOWN AND LOCKED POSITION MANUALLY. THE ACFT LANDED UNEVENTFULLY. MX TROUBLESHOT THE HYD SYS WITH NO DEFECTS NOTED. REPLACED THE HYD SYS PRESSURE SWITCH. C/W FUNCTIONAL TEST OF THE HYD SYS WITH NO DEFECTS NOTED. ALL WORK ACCOMPLISHED IAW MFG INSTRUCTIONS.