What was found
MKE/GRB - FLT 1074 - FIRST OFFICER NOTICED SPARKS EMITTING FROM THE RT ENGINE EXHAUST STACKS ON CLIMB-OUT. THE CREW NOTIFIED ATC THEY NEEDED TO MAKE A PRECAUTIONARY LANDING BACK AT MKE. CFR WAS CALLED OUT, THE CREW THEN MADE A SAFE LANDING AT MKE. WHEN MAINTENANCE INSPECTED THE RT ENGINE THEY FOUND THE COMPRESSOR HAD RECEIVED HEAVY FOD DAMAGE. THE ENGINE WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE. WHEN THE ENGINE IS SENT FOR REPAIR, AN INVESTIGATION WILL BE PERFORMED TO DETERMINE WHAT WAS INGESTED. (X)