Date: 201512
Local time of day: 0601-1200
Location: GFK.Airport, ND
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Skyhawk 172/Cutlass 172
Operator: FBO
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Final Approach
Airspace: Class D GFK
ATC / advisory: Tower GFK
Second aircraft: Skyhawk 172/Cutlass 172
Reporter organization: FBO
Reporter function: Pilot Not Flying; Instructor
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Commercial
Human factors: Situational Awareness; Communication Breakdown
Second reporter function: Pilot Not Flying; Instructor
Anomaly: ATC Issue All Types; Conflict NMAC; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Automation Aircraft Other Automation; Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: I was conducting stop and go's practicing traffic patterns and stabilized approaches with my student on Runway 35L at the Grand Forks International Airport (GFK). There were three aircraft that had been issued a clearance to land for Runway 35L. We were in Aircraft X on a left downwind; Aircraft Y was ahead of us on downwind making a short approach; and Aircraft Z was on a long final. Tower cleared Aircraft Y to land 35L (Number 1). Tower then cleared Aircraft Z to land 35L (Number 2). As we were abeam the numbers on downwind; Tower cleared us to land 35L (Number 2) and instructed us to follow the aircraft on final. I saw Aircraft Y making a short approach crossing over the threshold and considered them the aircraft on final and no factor. As we turned base to final; Tower advised us that we were supposed to be following the Cessna on final and immediately stated; 'Go around Left Side; Go Around Left Side. Start that turn westbound now. Aircraft Z Land.' I immediately took controls and conducted a go-around heading westbound breaking off from the final approach for 35L. This incident resulted in a near mid-air collision. We had been instructed to 'follow the aircraft on final.' However; I failed to recognize that tower had instructed Aircraft Z (the aircraft on a long final) to follow Aircraft Y (the aircraft making a short approach). From the time we had received our clearance to the time that Tower instructed Aircraft Y to taxi off of Runway 35L via Alpha 4 was nearly 15 seconds. I had assumed that the aircraft we were following was the aircraft on final over the threshold conducting the short approach. Tower had cleared two aircraft to land Number 2 for 35L (Aircraft X and Aircraft Z). As the PIC I failed to visually verify final and crosscheck/utilize the ADSB to verify that there were no other aircraft on final. I also failed to recognize that tower had cleared two aircraft Number 2 for 35L and that Aircraft Z had been instructed to follow Aircraft Y (the aircraft making a short approach). This situation could have been avoided if ATC would have cleared us Number 3 to land 35L or had advised us to follow the aircraft on a 2 or 3 mile final. Tower also failed to recognize that we had turned base prior to the aircraft on long final passing abeam us; which resulted in a near mid-air collision. Upon being instructed to go-around; I glanced at the ADSB which indicated we were 100 feet from the other aircraft on final. There were several contributing factors to this near mid-air collision: As the PIC I failed to recognize that two aircraft had been cleared Number 2 to land 35L; I failed to visually verify final and utilize the ADSB to verify there were no other traffic on final; Tower failed to recognize we had turned base prior to passing the aircraft on final; and Tower failed to issue a specific landing clearance as to which aircraft we were to follow such as; 'Follow the aircraft on a 2 mile final.' This situation emphasizes the importance of always maintaining vigilance for other aircraft in the area as well as the importance of clear and precise instructions from ATC when there are several aircraft operating in the traffic pattern.


Second narrative: My student and I were flying Aircraft Z and we were inbound to GFK on the VOR Rwy 35L approach in VMC conditions. Aircraft X; another C172 Skyhawk; was on downwind for Runway 35L. We had already been cleared to land on 35L; and GFK Tower cleared them to land on 35L; #2; behind another Cessna (us) on final. As my student and I neared Highway 2 at approximately 1;200 ft MSL; I noticed Aircraft X out of the corner of my eye. They were at our 10 o'clock; about 100 feet above and 100 feet in front of us; starting their turn from base to final. I took the flight the controls and initiated a turn and descent to the right. Simultaneously; GFK Tower told them; 'Aircraft X; you were supposed to follow that Cessna on final. Just go around left side; Aircraft X. Go around left side; and start that turn to the west now.' Aircraft X started the go-around and acknowledged GFK Tower. After returning to runway centerline; our approach was still stabilized; so I returned the controls to my student. GFK Tower also instructed us to land; so I responded that we would continue. We landed without further incident. After being instructed to turn downwind; Aircraft X apologized to GFK Tower and said; 'You had told us #2; so we were following that traffic that was already on the runway.' GFK Tower responded; 'Nope; nope; nope; nope. We never count traffic on the runway. It's always traffic prior to it.'As for corrective actions; if a pilot is ever unsure of which aircraft ATC is referencing during an instruction to follow another aircraft; simply ask. Also; make it a habit to check that final is clear before turning from base to final. Treat it like a three-way intersection.


Synopsis: Aircraft in the traffic pattern at GFK; reported misunderstanding the Tower Controller's instruction to land number 2 behind another aircraft on a straight in approach. The Tower had told the straight in pilot to land number 2 behind another aircraft on final and then the traffic pattern Cessna to land number 2 a few seconds later. The number 1 aircraft had landed in the meantime causing the confusion and resulting in a NMAC. The report from the Instructor of the straight in aircraft is also included.