Date: 201311
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Aircraft: PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Landing
Airspace: Class E ZZZ
ATC / advisory: UNICOM ZZZ
Second aircraft: Cessna 150
Reporter organization: Personal
Reporter function: Instructor; Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Engineer; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Other / Unknown; Situational Awareness
Anomaly: Conflict Airborne Conflict; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Airport; Human Factors; Procedure
Primary problem: Ambiguous

Narrative: I was beating up the pattern teaching a [new] student to fly and we were using Runway 31. The winds were 180/4 and a non-issue for landing on any runway. Runway 31 was in use with traffic when we arrived to enter the pattern. My student was on his first flight using the Sporty's Private Pilot syllabus and doing well in the pattern for his first time landing. After two landings; we were alone in the pattern and continuing to use Runway 31. While turning downwind for Runway 31 on our 3rd pattern; a Cessna 150 entered the pattern for Runway 21. This was no problem except the Cessna ended up on final for Runway 21 at the same time as we were turning final for Runway 31.  This was a potential conflict; however; we continued our visual VFR approach in VMC conditions from a left base with extra vigilance. As the Cessna was rolling out on Runway 21 for a full stop and getting close to the intersection of Runway 31 and 21; we were in the flare on Runway 31.  I directed my student to go around since I was not sure if the Cessna was going to stop before crossing Runway 31.  As we went around; I saw the Cessna taxi clear of Runway 21 at the Taxiway A just prior to the intersection of the runways.  He then taxied back to Runway 21 to takeoff. I continued to stay in the pattern for Runway 31; the active runway.  The Cessna then took off on Runway 21 to fly another pattern.  I had to take the controls from my student and aggressively reposition us on a non-standard downwind for Runway 31 to deconflict from the Cessna's turn to downwind for Runway 21.  After the Cessna conducted a low approach to Runway 21; he departed the pattern less than 500 feet underneath us as we were on another downwind for Runway 31.  Throughout our time in the pattern with the Cessna; the Cessna pilot was making unnecessary comments on the radio (Unicom frequency) wanting to know why we were using Runway 31.  I didn't respond at first as I tried to keep my emotions in check with a new student.  However; I explained to my student that this is not how you're supposed to fly a pattern and talk on the radio and that this not typical for general aviation flying.  Frankly; I was embarrassed that a new student had to see such unprofessionalism displayed on one of his first flights. We had originally entered the pattern hoping for Runway 13; but 31 was the runway in use so we used 31.  Runway 31 is also the ILS runway; is the longest runway and was working fine for my student with the current conditions. So; I don't understand why the Cessna pilot wanted to tangle with me in an unprofessional manner as I was trying to help a young student learn how to fly.  I finally made a comment to the Cessna on the radio; we were using Runway 31 because it was the active when we arrived and I have a new student learning to land and I'd appreciate it if he would not interfere with our training.  I called the FBO the next day to see if this Cessna 150 was based there.  They said no; however; they knew the pilot because he was previously based there and were not surprised by what happened.  The FBO had also heard the comments on the radio by him as he was using Runway 21. I've been flying for over 30 years and have never seen such in the pattern.  In addition; I'd like to add that there is nothing specifically written in the FAR/AIM or any FAA Handbook for crossing runway pattern operations and the best way to fly in such a pattern that overlaps with another.




Synopsis: PA-28 instructor in the pattern for Runway 31 with a new student reports a C150 entering the pattern for Runway 21 causing several conflicts before departing the pattern. The wind slightly favored Runway 21; but Runway 31 was in use when the instructor arrived and saw no reason to switch; which seemed to annoy the C150 pilot.