Small Aircraft
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1.5
Workload; Time Pressure; Situational Awareness; Confusion
Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Air Traffic Control Provided Assistance; Air Traffic Control Issued Advisory / Alert
Procedure; Human Factors
Typical early morning Local control session.  Traffic volume/complexity had not elevated enough to require opening the Local control 2 position.  Runways 35L/R were in use. Runways 9L/R were cold/inactive.  I was working parallel runways 35L/R combined.  Just prior to the runway 35L incursion; I had approximately 3 aircraft on frequency.  Aircraft X was IFR departing runway 35R eastbound; Aircraft Y in right-traffic runway 35R; and Aircraft Z holding short runway 35L awaiting departure for left-traffic runway 35L.  Aircraft A was approaching a 12-13 mile-final for 35L.  Aircraft Z called ready and I issued instructions to make left traffic runway 35L; scanned my final and runway 35L full-length; noticing a C172 in the run-up position on Bravo taxiway east of Alpha taxiway. Alpha taxiway parallels runway 35L and must be crossed on Bravo to reach runway 35L at Bravo intersection.  Anticipating Aircraft Z could make a tight pattern and arrive in front of Aircraft A; I informed Aircraft Z of Aircraft A's position and gave him the choice to either turn an early crosswind or expect an extension on the upwind and cleared him (Aircraft Z) for takeoff.  Aircraft Z replied in favor of the early crosswind and crossed the hold-short line for runway 35L with his takeoff clearance and started his departure roll.I then turned to the east and scanned runway 35R for Aircraft X departing and cleared Aircraft Y for the option on runway 35R.  As I was turning back to runway 35L to check my spacing/sequence between Aircraft Z and Aircraft A; I noticed my FLM working Ground Control reacting surprised facing runway 35L and broadcasting on his frequency to Aircraft B.  When I turned back west I had expected Aircraft Z to be having troubles during rotation; but soon realized he had rotated near runway 35L at A4 intersection (typical for students in this aircraft) and was climbing to a good altitude prior to turning his crosswind.  I then saw another Aircraft B taxiing southbound on runway 35L between the 35L at Bravo intersection and runway 35L at A3 intersection.  Knowing that Aircraft Z was in a critical phase of flight and nose up; I did not issue traffic on runway 35L as to not surprise the student and create another issue.  The amount of time I had once I had rescanned Aircraft Z's position and saw the conflicting aircraft (Aircraft B) on runway 35L was approximately 1-2 seconds.  Aircraft Z overflew Aircraft B with around 200-300 feet of vertical separation.  I then extended Aircraft Z's upwind waiting for Aircraft B to clear runway 35L.  Aircraft A checked on and I told him to continue.Aircraft B then exited runway 35L and was confused with ground controls instructions; so I waited to make sure he had turned into parking and then issued Aircraft A's landing clearance.  When Aircraft Z was in the upwind in stable flight I asked him if he was aware of Aircraft B on runway 35L; and he was not.  To me; this meant that he had already rotated and was climbing before Aircraft C incurred runway 35L.  At this time normal operations continued.This incursion is a tough one to prevent.  Aircraft must hold short of every runway and be issued a clearance to cross whether the surface is active or not.  This creates good and safe repetition for them.  [Student] Solo aircraft require a more active scan when working Ground Control.  Perhaps an additional requirement in our LOA for [solo] students to report when their run-up is complete; so that their next turn is monitored much more closely could help prevent this pilot deviation.  At the same time; these solo students have taxied to the same runways at least a dozen times before their first solo; and at that time the instructor joins us in the Tower Cab to assist.  They have to be trusted enough to understand their instructions in order to not overload the control positions.As CPC's; we work closely with [the local flight school]; and their solo students on a regular bases.  We understand the physical and emotional workload solo students go through here on a daily bases; as many of us went through the same training here in Grand Forks.  Our Sup/FLM's do not see or work near as many [solo] aircraft nor are they proficient at moderate levels.  This traffic was slow and not complex for Ground Control.  Low currency hours does not help these situations.  Perhaps FLM's should not be working any traffic unless all positions are split and the CIC is an FLM as well.  This would help place the responsibility for the FLM's working traffic on the FLM's.  With this said; I cannot guarantee that I would have caught this deviation in time to correct it; but my response would have been far more direct and time appropriate.  As CPC's we know to give near full attention to all [solo] students when able; especially during slow traffic. They take priority.
After arriving at work; I received a briefing and assumed responsibility for Controller-in-Charge (CIC); Flight Data (FD); and Ground Control positions.  Runways 35L and 35R were in use and active; Runway 9L and 9R were inactive; wind was light out of the west; and traffic was light.  The two controllers who opened; were relieved by myself and another controller assuming the responsibilities of Local Control; working operations on both Runway 35L and 35R.  Within five minutes of taking my briefing; Ground Control (GC) was given to another controller in order to split up work load.  At this time; the local flight school was beginning to pre-flight their aircraft; with just one aircraft in the pattern and two more taxiing out. A FLM CPC took the briefing for GC.  This left myself with CIC/FD combined and the same controller working LC; which is normal operation.  I began making a plan for the next shift of controllers scheduled to arrive; to provide relief for those of us in position at the time; split CIC from FD; and execute training on the necessary positions.  More aircraft began taxiing out; but traffic was still light.Aircraft C; a student-solo aircraft received standard taxi instructions to Runway 35L. They completed their aircraft runup in the assigned area; short of Taxiway A; which is parallel to Runway 35L.  When the aircraft began taxiing again; they failed to turn south on Taxiway A; as defined in the standard taxi instructions issued to them. Instead; Aircraft C entered Runway 35L at Taxiway B and continued southbound.  At this same moment; Aircraft Z flew over Aircraft C approximately 300 feet above them.  Aircraft Z had been cleared for takeoff for closed traffic prior to Aircraft C entering the runway; to my knowledge.  Aircraft Z; being in a nose-up attitude on their departure; was stated they were unaware of Aircraft C below them.As soon as Aircraft C's improper location was determined by ground control; they were issued taxi instructions to exit the runway.  The pilot exited the runway as instructed. At that point; it was determined that the student-solo in Aircraft C should not be departing.  The ground controller also gave them instructions to taxi back to the ramp at Taxiway A3.  The student pilot continued to taxi south on Taxiway A; with the controller issuing instructions back to the ramp at Taxiway G.  The student pilot still did not comply and continued southbound.  The GC issued the brasher warning at this time and further exiting instructions at Taxiway A4.  The student pilot complied with these instructions and exited taxiway A at A4.The Supervisor of Flight for the flight school was notified of the situation by telephone; and a report was created on the facility daily log.A possible improvement to prevent this in the future might be to have student solo pilots taxiing to Runway 35L advise when they are runup complete.  This will allow the ground control to continue with all of their other tasks without watching aircraft doing their run up.  Student solo pilots are often given more attention by ground control to prevent issues; but during busy traffic this special attention cannot be afforded.More active scanning on the tower team as a whole could have prevented Aircraft C from entering the runway; and confirming that they follow the assigned taxi instructions.
A GFK Controller reports of a runway incursion during a moderately busy session involving a student pilot.