As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4220 THE CREW REPORTED A DISTINCT BURNING SMELL ON APPROACH THAT SEEMED TO EMANATE FROM THE PACKS AND WHEN THROTTLE LEVER WAS AT HIGHER THRUST SETTINGS. THE AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. PERFORMED ETN EM 72-034 R4 WITH CREW AND FOUND NO EVIDENCE OF SMELL NOTED AT THIS TIME. NO PARTS REMOVED OR REPLACED. THE AIRCRAFT WAS RETURNED TO SERVICE.