Date: 202103
Local time of day: 0601-1200
Location: ZZZ2.TRACON, US
Flight conditions: VMC
Light: Daylight
Aircraft: Bonanza 33
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Cruise
Airspace: Class D ZZZ
Second aircraft: Bonanza 33
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Procedure
Primary problem: Procedure

Narrative: I was in level cruise at 11;000 [ft.] in clear VMC flying on an IFR flight from ZZZ to ZZZ1; following the filed airway on autopilot. I was on with ZZZ2 approach; the normal facility that handles this patch of airspace; and had received proper IFR advisories regarding other aircraft. My aircraft has an advanced glass panel with ADS-B In traffic information which I monitor as part of my scan - particularly when using the autopilot to reduce physical workload. Suddenly; I saw a traffic alert pop up on my avionics and it showed an aircraft at the same altitude; or within about 100 feet; very close to my location and approaching from behind with approximately a 30 knot overtake. The speed and the 000000 identifier confirmed that it was not an ADS-B 'ghost' and I became alarmed. I asked approach if they saw said airplane and I looked over my right shoulder; out the rear window to see a low wing; single engine airplane that I estimated was about the size of a BE36 or PA46 bearing down on me at high speed and a similar altitude. ZZZ2 said they had just seen the ADS-B target pop up and didn't know who it was and weren't talking to them. The aircraft was so close and approaching so fast that I immediately disconnected the autopilot and put my airplane into a rapid descent to avoid. The aircraft passed very close; but I was luckily below it by that time. ZZZ2 switched me to ZZZ3 Center and I also reported the same issue. The facilities had the aircraft on radar and ADS-B; but could not identify who they were. I found the target on a flight tracker app and was able to get the ICAO 24 Bit code; which identified the aircraft as a T34C (Ironically; a modified military trainer version of the aircraft I was flying). Not only was I affected; but other IFR and VFR aircraft had to contend with this unsafe behavior as well. The aircraft flew along it's merry way at primarily an IFR altitude; not talking to literally anyone. This was unsafe and improper. I have no idea if the folks flying that airplane saw me; but I sure knew I didn't want to find out and had to take immediate emergency action to avoid. There is simply no reason for military trainers to be off frequency; even VFR; for any reason. There is even less reason for them to violate regs and fly IFR altitudes while not flying under IFR.




Synopsis: Pilot reported taking evasive action to avoid a Near Mid Air Collision.