Date: 201708
Local time of day: 1801-2400
Location: FRG.Airport, NY
Aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower FRG
Second aircraft: Light Transport; Low Wing; 2 Turbojet Eng
Reporter organization: Government
Reporter function: Ground; Trainee
Human factors: Training / Qualification; Situational Awareness; Confusion; Workload
Second reporter function: Pilot Not Flying; Captain
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Detector: Person Air Traffic Control
When detected: Taxi
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Became Reoriented
Contributing factors: Company Policy; Human Factors; Procedure; Airport
Primary problem: Human Factors

Narrative: I took over the Ground Control position. Ground owned the inactive runway. I worked normally; taxiing aircraft back and forth across the inactive runway on their way to and from the active runway as needed. Due to volume and complexity; the local controller implemented Land and Hold Short (LAHSO) to bring in Aircraft X that had popped up on the radar. He requested runway 01/19 from me and I gave it to him; giving him the bar memory aid. I placed the vertical bars across my strip bays; as is the procedure here as a reminder when you give away your runway.As soon as Aircraft X landed and was rolling past my aircraft holding short; I requested the inactive runway back from local. He verbally gave me back the runway as well as the memory aid and I immediately continued working; removing my vertical bars; putting my Runway bar back in its place and picking up where I left off by crossing the inactive runway with aircraft. He also continued working on getting ready for his next departure; Aircraft Y. In the meantime; Aircraft X; being a large jet; rolled through the main intersection and exited the runway and called me for taxi back to the ramp. Getting him back would require him to now cross over the active runway. I kept my flow going and answered him right away telling him to taxi the same way I would instruct him if I owned the active runway.He seemed uncertain and responded with a crossing involving the Runway. I corrected him and repeated myself that he taxi via B and cross the active Runway. He read back the instructions and proceeded to begin creeping forward. Almost immediately the Local Controller said; 'Wait I'm departing ...!' Immediately after that the Controller in Charge (CIC) and another Controller in the tower jumped up and shouted at me to 'Stop that guy!' as they pointed to Aircraft X. Realizing what was happening and the mistake I'd made I keyed up immediately and said 'Hold short!' as I read the IFR strip for the call sign; then right away keyed up again and more specifically said; 'Aircraft X hold short.' At the same instant this was happening; the CIC and Controller also shouted at local to cancel Aircraft Y's takeoff clearance.Instantly local canceled Aircraft Y's clearance and instructed him to taxi clear of the runway which he did. Aircraft Y had just begun his roll and stopping was no trouble and likewise for Aircraft X; he had barely begun moving and stopped instantly but he was just over the hold short lines thus fouling the runway. As for why this incident happened; I can only attribute it to lack of practice using LAHSO and switching back and forth between runways in use in such a short amount of time. I had just trained on runway 01 the session prior to this and that was also still fresh on my mind.Leading up to the event was as follows. I certified on ground a few weeks ago and am currently early in my training hours on local. I began my day at XA00 with training on local with Runway 01 being the active. The traffic was extremely busy for me and my trainer took over. As developmental we are expected to follow along; move the strips; do the writing; and otherwise be prepared to jump right back into controlling traffic when your trainer hands it back to you. It's not uncommon to be taken on and off training multiple times during a one hour session as your trainer takes over for a few minutes and then hands the reins back over to you. I was completely immersed in the proceedings during that busy hour and once over; we went downstairs to debrief. This was just past XB00. My trainer very thoroughly went over mistakes; suggestions; and then we went into the conference room to use the whiteboard for more detailed dissection of the last hour's problems and other similar scenarios. Before we realized it the hour was up. At XC00 another controller going back upstairs to relieve the controllers on position shouted over that he was going up. We wrapped it up and immediately headed for the elevator to work once more without having taken a break at all that hour. Once upstairs I took over the ground position and began working. The incident happened about half an hour into this session.More familiarity and practice with Land and Hold Short Operations (LAHSO) and everything that it entails is my biggest recommendation at this point. I think adding clear verbal cues during complex operations could help tremendously as well. We already do this sometimes during crossings; verbally announcing 'I'm crossing now' (even though it's not required) to double check one final time that we all remember what we agreed to. During LAHSO; something like; 'I'm landing 01 now' or 'I'm departing 32 now' while everything is still in flux could help clear up any confusion and reaffirm where everything stands.


Second narrative: [Report narrative contained no additional information.]


Synopsis: A flight crew and Ground Controller reported the Ground Controller taxied them across an active runway that another aircraft was beginning its takeoff roll on.