As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPTAIN’S HAND MICROPHONE BEGAN TO CONTINUOUSLY TRANSMIT. AN EMER WAS DECLARED FOR LANDING. THE HAND MICROPHONE WAS DISCONNECTED TO ELIMINATE THE CONTINUOUS TRANSMISSION. THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. R & R CAPTAIN’S HAND MICROPHONE. OPERATIONAL CHECKED GOOD TO CONTINUE SERVICE IAW MM 23-00-00. THE ACFT WAS NOT GNDED.