Date: 202010
Local time of day: 1801-2400
Location: GAI.Airport, MD
Flight conditions: VMC
Weather elements / visibility: 10
Light: Dusk
Aircraft: Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Final Approach
Airspace: Class E ZDC
ATC / advisory: CTAF GAI
Second aircraft: Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Reporter organization: Personal
Reporter function: Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Human factors: Communication Breakdown; Training / Qualification
Anomaly: Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Procedure; Airport
Primary problem: Procedure

Narrative: I was acting as an instructor to a CPL who was new to flying the Aircraft X Type. He had spent all of his time up to this point flying the Aircraft Y Type; so I was helping him familiarize himself with the different aircraft. We were doing pattern work while several other aircraft were in the pattern.  Upon getting abeam the numbers and beginning our descent; there was an aircraft on long final (roughly 2-2.5 miles) that we did not hear on the radio.  We continued with our base; and final. The CPL whom I was instructing did not speak very strong english; and was having some trouble with the radio calls in the pattern; and occasionally neglecting to make them. In this instance; he neglected to call his base; and also neglected to call final.  I noticed this only after him turning final without saying anything; and immediately announced our one mile final. This set up a situation where a near miss occurred between us and the other aircraft who was on long final. The aircraft that was on a long final did not call an extended downwind; or a base.  They called final and neglected to give any mileage to indicate they had flown a much larger pattern than usual for a light general aviation plane. The other aircraft noticed us only because I called our final; and immediately broke off his final leg to avoid collision.  I spoke with their pilot after this incident and he said we were slightly above them and cut them off. I believe this incident was caused by a number of factors mentioned above; and could have been avoided with better radio work on the part of my aircraft and the other one on final.  I had a high workload at the moment; which caused my attention to lapse when the CPL turned base without making the call.  However; the pilot on the other aircraft also did not specify that he was purposely flying a large pattern with an extended downwind/base/final.  His failure and mine to accurately give position reports caused the incident.   I also believe that often pilots become complacent and fly a pattern which is far too large at this airport.  There are several times in a week where I have to extend my pattern to a point where I would not be able to make the runway in the event of an engine failure.  Routinely; general aviation aircraft at the airport fly a 2+ mile final; which should be considered a 'long' final.  Like in the incident mentioned; this can cause confusion when someone joins flying a smaller; more appropriate pattern.




Synopsis: Flight Instructor reported a NMAC of final resulted in Evasive action.