As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MCI - INFLIGHT CLIMBING THROUGH FL20, FLIGHT CREW HEARD A BANG AND SAW NR 2 ENGINE EXHAUST GAS TEMPERATURE DOUBLED AND LOSS OF N1 AND N2. AIR RETURNED TO MCI AND LANDED WITHOUT INCIDENT. FOUND SEVERAL MISSING FAN BLADES. REPLACED RIGHT HAND ENGINE. SYSTEM GROUND CHECKED NORMAL OPERATION.