bringing new benefits. Most important, the prototype leverages the advantages related to the embodied use of physical objects in physical space. Let’s observe two controllers working together to handle aircraft arriving at the Paris-Orly airport and see how their use of the system illustrates the beneficial properties of tangibility in such a critical activity.

In the scenario that follows, Paul is a planning controller. His role is to coordinate with adjacent sectors and prepare the flow of arriving aircraft for Tessa, a tactical controller, sitting next to him. Tessa’s role is to manage traffic in her sector, monitoring it on her radar display, and using radio communication to give pilots clearances for new altitudes, headings, or speeds.

Paul and Tessa share a set of paper strips arranged on a stripboard. Printed on each strip is the planned route of an aircraft through their sector.

Digital feedback for physical interactions. The system provides rich feedback, which increases the controllers’ confidence in the system, as it means the system “knows” what is happening.

It’s Friday at 4 p.m. Paul hears the strip printer and grabs a strip for the Turkish Airlines TH Y1825 flight, about to enter the sector and land at Orly. He puts the strip onto the stripboard and quickly analyzes the situation with this new incoming aircraft. The system displays a rectangular halo underneath the paper strip, colored in red to indicate the aircraft is an arrival (blue for departures). It also overlays the logo of the airline onto the strip, making it easier to locate it later on the stripboard. Some time afterward, the pilot of THY1825 calls. Tessa then underlines the aircraft call sign on the strip, to visually indicate the flight is now her responsibility.

Animated feedback is displayed on the radar screen, with a concentric circle designating the flight…

Connecting physical and digital
information. Strip’ TIC connects
the radar and stripboard views by
establishing a visual link between the
strips and the radar symbols.

Paul observes that TH Y1825 is
inbound to ODRAN, one of the three
main arrival beacons for Orly. A light
aircraft, call sign F-GFPS, is estimated
to transit at the same time. Paul wants
to inform Tessa as quickly as possible:
He takes the strip off the board to get
her attention, and points with his pen
at the ODRAN label on the strip. This
highlights all the representations of the
flights crossing this beacon in the near
future. Tessa immediately detects the
potential conflict over ODRAN and
decides to monitor it closely. Another
aircraft is now calling: “Good afternoon,
this is Lufthansa 8950, descending
Flight Level 90 (approx. 9,000 ft.),
inbound ODRAN.” Tessa cannot find the
corresponding strip on the board—the
planner may have put it in an unexpected
place. Fortunately, the flight is highlighted
on the radar display. She points at it to
have the strip highlighted too.

Real-time paper strips. Ink printed on paper is not dynamic, which forces controllers to reprint strips when they want updated information. Besides, real-time data is available only on the radar display, which requires the controller to mentally consolidate the available information.

Thanks to the real-time projection of aircraft altitudes onto strips, Tessa notes that THY1825 is reaching its assigned flight level 90. She decides to allow the aircraft to descend farther, contacts the pilot, and gives a new altitude: 3,000 ft. She records this clearance by circling the pre-printed 3,000 ft. label on the

The prototype leverages
the advantages related
to the embodied use
of physical objects in
physical space.

Strip'TIC mixes paper and electronic strips. The system tracks controller actions and pen input simultaneously (here filtering on a beacon started from an interaction with the paper strip).