As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOST RADIO COMMUNICATION. EMERGENCY DECLARED, FLIGHT RETURNED TO DEPARTURE. LANDED WITHOUT INCIDENT. AIRCRAFT WAS GROUNDED. REMOVED AND REPLACED BOTH HIGH FREQUENCY COUPLERS IAW AMM 23-11-03 AND LEFT HIGH FREQUENCY TRANSCEIVER IAW AMM 23-11-05. OPERATIONAL CHECK GOOD. SEE ALSO AALA20161218005.