Narrative:

I was on a personal cross country flight [when] I spotted another aircraft at the same altitude which appeared to either be flying away from or towards me. After a few moments it became apparent that the aircraft was on a head on collision course so I altered my heading approximately 20 degrees to the right to provide adequate separation. In an effort to make my aircraft more visible I also turned my landing lights on. Initially my course change appeared to resolve the conflict; however at approximately 1/4 mile distance the other aircraft turned towards me again on a collision course. At that moment I executed an aggressive right hand turn; however when I did the other aircraft turned hard left. I lost sight of the other aircraft due to my bank angle however; when I regained visual contact; the other aircraft was approximately 20 feet to my rear left and had our speeds not been so closely matched would have likely struck the left side of my aircraft. I could clearly see only one male occupant and it did not appear as though he saw me. After the incident I continued on my original course and made a traffic advisory on 123.0 and attempted to establish contact with the other aircraft but did not get a reply. Approximately two hours later on my return flight while overflying the same area I saw the same aircraft so made several circles well above and took several pictures to establish its identity. The aircraft was making continuous low passes over the ground and appeared to be searching for something. After viewing the images I discovered the words 'state patrol' painted on the tops of the wings and could read its 'north' number. After continuing to my destination I was able to establish radio contact with the pilot after several attempts on 123.0 using his tail number.

Related reports:

Google
 

Original NASA ASRS Text

Title: While on a cross country flight a C-172 pilot suffered an NMAC with another aircraft later identified as a State Patrol aircraft.

Narrative: I was on a personal cross country flight [when] I spotted another aircraft at the same altitude which appeared to either be flying away from or towards me. After a few moments it became apparent that the aircraft was on a head on collision course so I altered my heading approximately 20 degrees to the right to provide adequate separation. In an effort to make my aircraft more visible I also turned my landing lights on. Initially my course change appeared to resolve the conflict; however at approximately 1/4 mile distance the other aircraft turned towards me again on a collision course. At that moment I executed an aggressive right hand turn; however when I did the other aircraft turned hard left. I lost sight of the other aircraft due to my bank angle however; when I regained visual contact; the other aircraft was approximately 20 feet to my rear left and had our speeds not been so closely matched would have likely struck the left side of my aircraft. I could clearly see only one male occupant and it did not appear as though he saw me. After the incident I continued on my original course and made a traffic advisory on 123.0 and attempted to establish contact with the other aircraft but did not get a reply. Approximately two hours later on my return flight while overflying the same area I saw the same aircraft so made several circles well above and took several pictures to establish its identity. The aircraft was making continuous low passes over the ground and appeared to be searching for something. After viewing the images I discovered the words 'State Patrol' painted on the tops of the wings and could read its 'N' number. After continuing to my destination I was able to establish radio contact with the pilot after several attempts on 123.0 using his tail number.

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.