Date: 201908
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
ATC / advisory: Center ZZZ
Aircraft component: VHF
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Second reporter function: Captain
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Other / Unknown
Detector: Person Air Traffic Control
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Human Factors; Procedure; Company Policy
Primary problem: Ambiguous

Narrative: Flight to ZZZ; which was reporting WX Clear skies and unlimited visibility. Flew company route. After ZZZZZ cleared direct ZZZZZ1 direct ZZZ ( ZZZZZ4 Arrival). Prior to TOD; ATC cleared (flight) to descend via ZZZZZ4 Arrival ZZZ. Also prior to TOD a Company Dispatch sent us an ACARS message requesting a test message on ACARS to Dispatch and Maintenance. We sent a test text message to Dispatch and Maintenance on ACARS. We then received confirmation the test text message was received on ACARS from company. Shortly thereafter we got a message stating ACARS voice-on ACARS; it said ACARS voice mode. Neither of us had seen this message before. In our descent and after the unusual ACARS voice mode message we experienced Lost Communications with ZZZ Center. We made numerous attempts to establish communications with ATC on both radios. No matter what frequency selected it transmitted and received only on company frequency. We were locked in only on [company frequency]. We squawked 7600 on our Transponder for Lost Communications. We also communicated with other [Company] flights so they could relay our problem to ATC. Eventually we were able to have ATC patched through on company frequency thereby receiving a clearance for a visual approach to ZZZ; cleared to land Runway XXR and taxi to gate. Flight was conducted safely. There is no QRH NG checklist for Lost Communications. Relying only on cumulative flight experience of flight crew. We did as best we could. Same. In QRH establish Lost Communications Procedure/Checklist.


Second narrative: Prior to ZZZZZ; requested direct ZZZZZ1 - ZZZZZ4 Arrival into ZZZ. Cleared as requested. Prior to top of descent; cleared descend via ZZZZZ4 Arrival. Dispatch asked us to do a Dispatch and Maintenance ACARS test. We sent them both messages and Dispatch messaged back that the tests were good. We then got a FMC message saying ACARS voice;on ACARS; it said ACRS voice mode - (name) and I had never seen that message. When I tried to call out of FL360 to ZZZ Center- the #1 radio had no COMM or Receiving [so] I tried the #2 radio. Changed from Company [frequency] to Center. I transmitted. Company told us we were on Company frequency. I realized we were stuck on Company. I asked ZZZ Ops to relay and realized he didn't understand; [so] I asked for a pilot. Another pilot answered and I explained our problem; she relayed for us. She told us to squawk 7600 and cleared us for the No Comm on ZZZZZ4 Arrival. She then came back and said TRACON was going to transmit on Company to clear us. They came on and cleared us to continue on ZZZZZ4 Arrival. I told them we had ZZZ airport in sight; were cleared for a visual to [Runway] XXR and cleared to land. After landing; we were cleared to cross [Runway] XXL and cleared to parking. Then we were given a number to call. I called the number and was informed that we crossed ZZZZZ4 too low. I told her that I thought we were cleared direct to ZZZZZ1 - so ZZZZZ4 didn't matter. I was then informed that the tapes were being pulled and that we broke some altitude on the ZZZZZ4 Arrival. I told her it was busy up there but I didn't think we did.


Synopsis: Flight crew reported experiencing partial loss of communication during approach.