What was found
BURNING SMELL IN COCKPIT DURING FINAL APPROACH WHILE FLYING THROUGH HEAVY RAIN (FLT 4289 FILED CLOSED)FLIGHT CREW VERIFIED THAT ON FINAL APPROACH IN HEAVY RAIN BURNING SMELL ONLY LASTED FOR 3-5 SECONDS AND NEVER RETURNED, PREFORMED GVI OF CABIN AND COCKPIT AND USING VARIOUS ELECTRICAL LOADS AS NEEDED NO BURNING SMELL NOTED AND FOUND NO TRIPPED CB'S, COULD NOT DUPLICATE, VERIFIED NO 10 DAY HISTORY, NO FURTHER MX ACTION REQIURED.