As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF LANDING GEAR WOULD NOT RETRACT. SPOILER UNLOCKED ILLUMINATED AND AUTO THROTTLES DISCONNECTED AND WOULD NOT RE-ENGAGE. AIR RETURN TO DTW. MAINTENANCE NOTED GEAR (MAIN) TO BE BADLY ICED UP SENT TO HANGAR FOR THAW. PERFORMED GEAR SINGS IAW AVRO MM CHAP 32. ALL CHECKS GOOD.