Narrative:

During a local flight in my airplane; another aircraft seemed to intentionally fly toward me as if to join up. As I had no communication or coordination with the other aircraft; its intentions were unknown to me; so to avoid a possible midair collision; I chose to take evasive action; and turned away from the other aircraft. I also descended while in the turn only to see the ads-B in display of other aircraft follow me in the turn and the descent. I could not tell exactly how far away from me the other aircraft was; and I could not visually see it; but my traffic display showed the other aircraft with no vertical separation and little or no lateral separation. The initial right turn and descent was started from approximately 1500 ft. MSL; and a 340 degree heading; all the way down to about 700-800 ft. MSL; and a heading of 160 degrees. At that time the other aircraft was still closing; following my evasive action. I then made a left; 360 degree turn at 800 ft. MSL; and the other plane continued southeast bound and climbed to a higher altitude. I then returned to ZZZ. During the maneuver; I broadcast on 122.75 to try and raise the other aircraft; but I did not receive a reply. My aircraft is equipped with ads-B in; so the registration number of the other aircraft is tagged with its position and altitude on my display screen. During my evasive action it was not possible to know if the other aircraft was not about to collide with mine. The information on my traffic display showed the other aircraft to actually be on top of me with a vertical separation of +/-0 feet. Needless to say this situation could cause a pilot to take such severe action as to jeopardize safety of flight and cause an accident. It seemed clear the other aircraft intentionally closed on mine and followed me through evasive maneuvers while continuing to close. The other aircraft also changed altitudes to follow me according to my traffic display.the flight and the event occurred about 9 miles north northwest of ZZZ.

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Original NASA ASRS Text

Title: Pilot flying C-170B aircraft encountered near mid-air collision with another airplane.

Narrative: During a local flight in my airplane; another aircraft seemed to intentionally fly toward me as if to join up. As I had no communication or coordination with the other aircraft; its intentions were unknown to me; so to avoid a possible midair collision; I chose to take evasive action; and turned away from the other aircraft. I also descended while in the turn only to see the ADS-B in display of other aircraft follow me in the turn and the descent. I could not tell exactly how far away from me the other aircraft was; and I could not visually see it; but my traffic display showed the other aircraft with no vertical separation and little or no lateral separation. The initial right turn and descent was started from approximately 1500 ft. MSL; and a 340 degree heading; all the way down to about 700-800 ft. MSL; and a heading of 160 degrees. At that time the other aircraft was still closing; following my evasive action. I then made a left; 360 degree turn at 800 ft. MSL; and the other plane continued southeast bound and climbed to a higher altitude. I then returned to ZZZ. During the maneuver; I broadcast on 122.75 to try and raise the other aircraft; but I did not receive a reply. My aircraft is equipped with ADS-B in; so the registration number of the other aircraft is tagged with its position and altitude on my display screen. During my evasive action it was not possible to know if the other aircraft was not about to collide with mine. The information on my traffic display showed the other aircraft to actually be on top of me with a vertical separation of +/-0 feet. Needless to say this situation could cause a pilot to take such severe action as to jeopardize safety of flight and cause an accident. It seemed clear the other aircraft intentionally closed on mine and followed me through evasive maneuvers while continuing to close. The other aircraft also changed altitudes to follow me according to my traffic display.The flight and the event occurred about 9 miles North Northwest of ZZZ.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.