As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT THE CREW WAS UNABLE TO COMMUNICATE WITH ATC DUE TO A FAULTY PILOTS SIDE AUDIO CONTROL PANEL PN 75110010-909 THAT DISABLED THE PILOTS & CO-PILOTS RADIOS ON ALL THREE COMMUNICATIONS SYSTEMS. THE FAULT WITH THE AUDIO CONTROL PANEL WAS SIMILAR TO HAVING A STUCK MIC. THE DEFECTIVE CONTROL PANEL WAS REPLACED WITH REPLACEMENT UNIT. OPERATIONS CHECKED OK. THE ACFT WAS RETURNED TO SERVICE.