Busy airspace leads to near-miss during training flight

This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.

Me and my student were on an IFR flight plan and were communicating with Approach. We were maintaining 4,000 feet as assigned. Approach advised us that there was traffic in the opposite direction, indicated 3,500 feet, a Cherokee.

At that time there were several other traffics in the area. We saw the traffic passing below us in the opposite direction with a safe separation, so we advised ATC that we had the traffic in sight.

I also confirmed with the ADS-B traffic on the MFD that they were at least 500 feet below us and would not create any collision hazard.

Approach then handed us off to another frequency. While switching frequency on the MFD, I saw another ADS-B traffic alert on the MFD approaching us from the left. The traffic seemed to be maneuvering, climbing rapidly, and converging with us at the same altitude.

I immediately looked up and saw an aircraft passing underneath us from left to right. The separation would have been less than 200 feet.

I make a call to approach and advise them that we just had a traffic crossing beneath us almost the same altitude. The controller acknowledge but did not give us any other information. Approach did not advise us of that traffic either prior to handing us off.

What I would have done different would be to keep my eye outside more, especially near the area with high volume of flight training activities. Multiple traffics in the area made it harder to judge which one is closer or heading toward us. I was busy setting up frequency and reading approach plate, where I lose sight of the outside traffic for a moment.

I also wouldn’t rely too much on ATC to provide traffic information in busy airspace, even on IFR flight plan.

Primary Problem: Environment — Non Weather Related

ACN: 1869576