Date: 201602
Local time of day: 0601-1200
Location: GTF.Airport, MT
Flight conditions: VMC
Weather elements / visibility: 40
Light: Daylight
Aircraft: Small Aircraft
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Final Approach
Airspace: Class D GTF
ATC / advisory: Tower GTF
Second aircraft: Small Aircraft
Reporter organization: Personal
Reporter function: Instructor
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Human factors: Situational Awareness; Distraction; Confusion; Training / Qualification
Second reporter function: Local
Anomaly: ATC Issue All Types; Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Separated Traffic; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: I was giving instrument instruction in Aircraft X at Great Falls International Airport (GTF); Montana.  My student and I had done 4 practice instrument approaches and were on final and cleared for our 5th approach; RNAV Y Runway 21.  The student was wearing goggles.  Aircraft Y; was working in the traffic pattern.As we intercepted the final approach course; 8 - 9 miles from the approach end of Runway 21; we heard the control tower clear Aircraft Y for the 'option' on Runway 21 and tell them to make a 'short approach'.  The controller told us Aircraft Y was on a 'right downwind'.  We were slowed to about 95 knots indicated for the approach and were doing about 73 knots groundspeed driving into a fairly strong wind.  I was looking hard for Aircraft Y; but could not locate it.  Just inside of DEELM/glide slope intercepted less than 5 miles from the runway I still had not located the Aircraft Y traffic. Consequently; I asked the tower to 'say the location of the traffic'.  The controller stated the traffic was on a 'short right base'.  I looked carefully and still could not locate it.  I replied 'negative contact' hoping the tower would better pinpoint the Aircraft Y's location.At about that time; I looked to the right and saw Aircraft Y about 300-500 feet to our right and slightly above us.  Just as I spotted it; the tower instructed Aircraft Y to 'go around'.  That instruction was 'stepped on' so I asked the tower to clarify which aircraft was to 'go around'.  Tower stated Aircraft Y.  I then asked tower to confirm that Aircraft X was 'cleared to land'.  They replied in the affirmative.We landed; taxied to parking and shut down.  Speaking with the student pilot and instructor who were in Aircraft Y after [their] landing; they stated they had not seen us until last minute as well.I believe I took appropriate action in requesting the tower to help us locate the traffic; and by advising them of our continued inability to locate it.  I believed they had both aircraft in sight and would issue instructions to one; or the other; of us to deviate from our previously cleared flight paths in order to avoid a conflict.  My next thought; had I still not been able to see the traffic; was to request to turn off from final and get vectors back for another approach.Constant vigilance/'see and avoid' in the traffic pattern; even at tower controlled airports and in VMC; is an absolute must for all pilots. Perhaps the controllers were distracted (working together in the tower cab) as just prior to the above incident the approach controller was late in giving us an intercept vector to final causing my student to ask if approach was going to give us a turn.  My response was for him to query them (a teaching point).  He did and got a hurried 'turn right heading 180; maintain 6;000 'til established; cleared for the RNAV Y 21 approach'. We turned immediately; but ended up flying through the final approach course and having to re-intercept due to the lateness of the instruction.  This was followed by the above noted incident when passed to tower.


Second narrative: I was working Local Control. Aircraft Y was in right closed traffic for runway 21; Aircraft X was doing a practice instrument approach to runway 21. Aircraft X was on a 3-5 mile final; Aircraft Y was on a midfield right downwind. I instructed Aircraft Y to make a short approach and told him about the Aircraft X traffic. I then told Aircraft X he was following Aircraft Y on a midfield downwind. I was able to see both aircraft at all times; but the aircraft did not see each other. Aircraft Y ended up flying approximately a 1 mile base. The Front Line Manager (FLM) said he did not think it was going to work; I mentioned that I thought it would. Very shortly after we came to the determination that it would not. I instructed Aircraft Y to go around; Aircraft X then landed on runway 21 close behind Aircraft Y going around.


Synopsis: GTF Local Control and a pilot of one aircraft reported an NMAC. Tower Controller instructed one of the aircraft to go-around in order to separate the traffic.