As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4278 THE CREW REPORTED THAT DURING THE CLIMBOUT WHILE DOING AN ANTI-ICE TEST, HAD A BURNING ODOR IN THE COCKPIT AND CABIN. THE CREW CONTINUED ON TO ORD AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. GROUND RAN ENGINES IAW ETN EM-72-034 R4, NO SMELLS, SMOKE OR DEFECTS NOTED AT THIS TIME. NO PARTS REMOVED OR REPLACED. THE AIRCRAFT WAS RETURNED TO SERVICE.