Date: 201601
Local time of day: 1201-1800
Location: HUF.Airport, IN
Flight conditions: VMC
Light: Daylight
Aircraft: Small Aircraft
Operator: FBO
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Landing
ATC / advisory: Tower HUF
Second aircraft: Small Aircraft
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Developmental
Human factors: Workload; Situational Awareness; Distraction
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic
Contributing factors: Procedure; Human Factors; Staffing
Primary problem: Staffing

Narrative: This event was brought to my attention; and reviewed with me by my ATM (Air Traffic Manager) as a result from a random audit. The event took place on a nice VFR day. HUF was operating TRACAB due to the lack of staffing and for training. That day we were 2 people short in the morning; with only 3 CPC's and Local 1 trainee. Having only 3 CPC on a nice VFR day was not good because the Flight School operations scheduled and history proves that we get really busy during these conditions. I was the local control; ground control; and flight data all combined for the majority of; I believe over an hour session. As soon as the first aircraft called in this session; it seemed it didn't stop for over an hour. The radar controller was using my DBRITE which is local control's primary tool to work with; and his traffic was on heavy; and complexity was heavy with opposite direction approaches being conducted; with some crossing runway operations at times. During the event; there were radar approaches being conducted; sometimes opposite directions; and multiple aircraft in the VFR Tower Pattern mixed. Situation: Aircraft X; CAT 1 was VFR Pattern Traffic requested Full Stop (FS) and was cleared Full Stop. Aircraft Y; CAT 1 was VFR inbound for FS; cleared for the Option; but verified FS by me behind Aircraft X. Aircraft Y responded with affirmative FS. On a separate transmission; Aircraft Y keyed up and said 'Tower verified cleared for the Option?' and I responded with Affirmative (This time I HAD 5 airplanes on my frequency). I remember that because of my initial evaluation of the situation; I anticipated that Aircraft X will be off either on TWY A2 or A3; I was confident that leaving the option clearance was not an issue. However; when I look for Aircraft X to clear him of the runway after he landed; I instructed him to get off on A3; but he reported he was already crossing Runway 14 which was already around 7000ft down the Runway 5; I looked for Aircraft Y out the window and it looked that I had separation as he appeared he was still 1/2 [mile] from runway threshold. I instructed Aircraft X to turn off at the end as he was taxiing really fast. As I recall; Aircraft X was off the Runway when Aircraft Y just about over threshold; nearly 40 seconds passed after Aircraft X had reported crossing Runway 14 taxiing in fast speed. Aircraft Y although cleared for an option; which includes FS; did a FS and I had separation. This situation made complicated because of Aircraft X's unusual action where he either landed long; or landed and passed 2 taxiways without exiting in the very next possible taxiway. This has occurred before where these aircraft would simulate a landing without applying breaks until way down the runway but do not advise the tower prior.  This particular runway configuration; Runway 5 (9021ft long) being used as primary runway; makes it very hard for aircraft to be seen from the tower which is at the very end of the runway. When this event occurred; Arrival control was very busy with a tracker called to help; and I was also very busy on a TRACAB Ops; and side by side working there were plenty of distraction. The staffing was extremely short; TRACON was not opened so we could accomplish training working together in the tower. It is an unsafe environment to work in due to almost no equipment aid for me; the local controller in this situation. This staffing situation is an ongoing problem at HUF. Procedure listed in Chapter 3 of the Joint Order; 7110.65 Section 3-8-1 Note: 'The 'cleared for the option' procedure will permit and instructor/examiner/pilot the option to make a touch-and-go; low approach; missed approach; stop-and-go and Full stop landing.' Aircraft Y did a full stop and was given taxi off instruction shortly after; and therefore I did not break any runway separation. Although; I could've have re-cleared the aircraft for full stop; but as I mentioned above; when I initially and subsequently evaluated the situation; full stop clearance was not necessary. As I listened to the tapes on my own; it reaffirmed to me that Aircraft X was turned off at the end; as he was taxiing very fast on the runway when Aircraft Y crossed the threshold; after nearly 40 seconds had elapsed.A. Procedure listed in CH3 of the 7110.65 Section 3-8-1 Note: 'The 'cleared for the option' procedure will permit and instructor/examiner/pilot the option to make a touch-and-go; low approach; missed approach; stop-and-go and full stop landing.' Aircraft Y did a Full Stop and therefore I did not break any runway separation.B. Having the appropriate staffing will eliminate this issue as it will eliminate distractions in the tower when both tower and radar working heavy workload; TRACON will be opened; and positions will be split during these times. C. Safety meetings or frequent collaborations with [a local] Flight School; on how to improve smoother operations. I have not heard of any meetings with the flight school which included inputs/questions perhaps solicited from us controllers or vice versa. Flight School schedules flights daily. Frequent communications and touching base with the controllers and flight school and vice versa will help in improving any possible operational issues in the actual world; by affording such collaborations byway of; for example question and answer.




Synopsis: HUF Tower Controller reported they had a shift where the facility was short staffed; problems with a flight school; and an aircraft that was told to exit at a specific taxiway; but exited at a different taxiway due to its speed. Controller thought he might have to send aircraft on final around; but did not have to because the aircraft made a full stop landing when cleared for the option.