As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 440 MCO-BOS, CREW DECLARED EMERGENCY AND AIRCRAFT RETURN TO MCO DUE TO LOUD VIBRATION/THUMPING BANGING NOISE UNDER COCKPIT FEET AREA EVERY 10-15 SECONDS. SPOILERS SHOWED ARMED IN FLIGHT, NO OTHER INDICATION SPEED BRAKE INDICATION ON. TROUBLESHOOT AND FOUND WX RADAR RECEIVER / TRANSMITTER MAKING A THUMPING SOUND EVERYTIME IT MOVE TO THE LEFT. REMOVED AND REPLACED WX RADAR TRANSCEIVER IAW 34-42-01. OPS CHECK GOOD, NO DEFECTS NOTED, NO FURTHER THUMPING SOUND HEARD.