As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT #3105 AFTER GEAR RETRACTION AFTER TO, CREW RECEIVED A HYDRAULIC MC ON CWP. HYDRAULIC FLUID QUANITY WENT TO ZERO. MAIN ACCUMULATOR WENT TO ZERO. PERFORMED QRH AND PERFORMED EMERGENCY GEAR EXTENSION. AIR RETURN TO DTW. MAINTENANCE INSTALLED NEW HYDRAULIC SWIVEL PN L387105A. PERRFORMED OPS CHECKS IAW SF 340 AMM CHAPO 32. ALL CHECKS GOOD AT THIS TIME.