Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 100; Flight Crew Total 1500; Flight Crew Type 60
Time Pressure; Situational Awareness
Conflict NMAC
Flight Crew Took Evasive Action
Company Policy; Procedure
We were beginning to descend from our cruise at 2;500 ft. when Aircraft Y descended on top of us from head on. I hadn't seen the airplane until it filled my windshield. We quickly put Aircraft X into a descending left hand turn because Aircraft Y was slightly to the right side of our aircraft. The plane did not appear to have seen us because they didn't make an effort to turn or climb. It is not uncommon for [university] airplanes to appear completely clueless about whats going on around them. I believe the main cause of the issue was pilot traffic scanning; and maintaining focus outside the cockpit while flying visually. We did not have an ADS-B (Automatic Dependent Surveillance - Broadcast) transponder on board so if they were relying on their ADS-B traffic system to show where we were; then it would not have worked. I don't know why I hadn't found it until as late as it was because I was actively scanning for traffic; and the student I was flying with is a seasoned aviation professional as well. I have already had a conversation with our flight school about staying aware when we are out flying; and will further remind everyone at our next staff meeting.
Flight Instructor reported a NMAC resulted in taking evasive action.