As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT RADIO MANAGEMENT UNIT NUMBER 2 WAS FROZEN AND WOULD NOT TUNE TO ANY FREQUENCY AND THAT RADIO MANAGEMENT UNIT NUMBER 1 WOULD REVERT TO A PREVIOUS FREQUENCY APPROXIMATELY 30 SECONDS AFTER IT WAS SET. THE CREW RETURNED TO FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE RADIO MANAGEMENT UNIT NUMBER AND RE-RACKED THE RADIO MANAGEMENT UNIT NUMBER 1, OPERATIONAL CHECKS WERE GOOD.