Cessna 210 Centurion / Turbo Centurion 210C; 210D
Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 45; Flight Crew Total 4000; Flight Crew Type 1800
Communication Breakdown; Situational Awareness
ATC Issue All Types; Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Air Traffic Control Issued Advisory / Alert
Airspace Structure; Human Factors
We were cleared direct to [destination airport] at 3000 feet and my traffic system sounded an alert showing a target almost directly ahead and 100 feet higher. I identified the traffic about 500 feet to my left as it went by. I asked the controller if he had noticed the target and he stated that he had been trying to call me and the pilot of the target plane but neither of us answered. I told him that I never heard his call. The other pilot said he had heard the call and had responded.Since I'm not sure why I didn't hear the call; I can only assume that perhaps I was focused on other tasks or there was a communications problem. In the future I will try even harder to make sure that one ear is always listening. Perhaps the controllers should re-transmit if an alert is not acknowledged quickly.The Traffic Avoidance System was an important factor in this case and well worth the investment.
The pilot of a C210 was alerted to a near-mid-air-collision by the onboard traffic system. ATC was reported to have tried to contact both aircraft; but an unknown communication problem existed.