As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING GEAR RETRACTION ON TAKEOFF, THE LEFT MAIN GEAR DID NOT RETRACT. RECYCLED GEAR ONCE AND GEAR INDICATION ON LEFT GEAR WAS NORMAL WITH DOOR DISAGREE INDICATION. AIRCRAFT RETURNED TO DTW AND LANDED WITHOUT INCIDENT. DTW MAINTENANCE PERFORMED INSPECTION AND GEAR RETRACTION AND EXTENSION OF LANDING GEAR SYSTEM, OPERATIONAL CHECK OK.