Date: 201405
Local time of day: 1801-2400
Location: FAR.Airport, ND
Light: Daylight
Aircraft: Small Aircraft; High Wing; 1 Eng; Fixed Gear
Flight plan: VFR
Flight phase: Final Approach
Airspace: Class D FAR
ATC / advisory: Tower FAR
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Confusion; Training / Qualification
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Procedure; Environment - Non Weather Related
Primary problem: Procedure

Narrative: Aircraft X was in traffic pattern on Runway 36 and requested Runway 27 for crosswind landings. I was performing OJT with a trainee that was on only his second hour of Local Control. He put Aircraft X in the right downwind for Runway 27 and was wondering if he should extend him because we had a jet call ready for departure Runway 36. About the same time another aircraft checked on inbound for Runway 36 and the trainee asked a general question about whether to clear him to land or have him report final. We cleared the jet for departure Runway 36 to get him through the intersection of Runway 27 before Aircraft X even turned base; then cleared Aircraft X for the option Runway 27. We forgot to get Runway 27 from Ground Control and he had an airport vehicle just finishing up a runway check on Runway 27 west of Runway 36. I had scanned the runway and somehow missed the vehicle who was about to exit at C5 Taxiway (the departure end of 27); when Aircraft X asked; if there was a vehicle on the runway. We then noticed the airport vehicle exiting at the end and instructed Aircraft X to go-around prior to them crossing the threshold. They went around and reentered the downwind for Runway 27. We had the correct runway strips in our strip bay; but failed to do a proper scan of that. Had we done a proper scan of our strip bay; we would have noticed we didn't own Runway 27. Ground Control had some things going on so he wasn't aware of the situation.The only recommendation would be for me to improve my runway/strip bay scan that would have alerted me to the vehicle on the runway. I always check the runway; but maybe the vehicle was behind one of the pillars that separate the Tower windows and I missed him. We teach our trainees how important it is to scan the runway and since he was so new on position; it didn't take many aircraft for him to feel a little overwhelmed. The only other recommendation I have is to always have vehicles contact Tower (Local Control) prior to going on any runway. It is something that would have to change in our SOP and our LOA with the airport; but I believe would have prevented this from happening. This is an isolated incident here at Fargo; so I don't believe it is a procedural (SOP or LOA) problem; but rather just a mistake by my trainee and myself.

Callback: Reporter stated that the norm of the facility is to use red strips with the runway number on it to show runway is owned by another position. A green strip with runway number indicates ownership of the runway. He stated that the strip showing red Runway 27 was indeed in front of him; but did not see it because the trainee blocked his view. Discussion was then had about possibly keeping the runways assigned to Local Control even though they were closed instead of giving them to Ground Control.



Synopsis: Controller reports aircraft on final asks if a vehicle is on runway they are cleared to land on. Controller realizes he doesn't own runway currently and sends aircraft around.