In a comment @randomhead mentioned:

Remote towers are already in use at several sites in multiple countries. Off the top of my head and without even googling, there's Leesburg airport in Virginia

From this article I found the following:

The FAA has declared the Saab remote tower system at Virginia’s Leesburg Executive Airport (KJYO) “operationally viable,” authorizing ATC services to continue there using this system.
The system at Leesburg includes fixed high-definition cameras and controller displays, as well as maneuverable optical and infrared cameras, microphones, and signal light gun. Controllers at the remote tower have the same tools as at other ATC towers, but use live video displayed on monitors instead of direct vision to detect and direct in-view air traffic.
“This milestone FAA decision has positioned the Leesburg airport—the second-busiest general aviation airport in Virginia—one step closer to permanent ATC services, while avoiding the ever-increasing expense of constructing and maintaining a conventional, multi-story ATC tower,” Saab said.

I’m curious if anyone knows how the light gun is controlled and actuated. Is it aimed visually by the operator or does it make use of a targeting system using dedicated cameras or radar?


2 Answers 2


The light gun is shown in this press release photo from Saab Sensis. It appears to be on a multi-axis pedestal with a camera, likely for tracking purposes.

Edit:Link to article with pictures

Saab remote light gun

  • 1
    $\begingroup$ Thanks. Any information on the user interface? How does a controller point the gun? Joystick? Touchscreen? If an a/c is squawking 7600 can the controller tell it to automatically lock on and follow it? What if it’s just squawking 1200. Or has no xpndr at all? $\endgroup$
    – Jim
    Commented Mar 8, 2022 at 14:56
  • $\begingroup$ @Jim unfortunately not. I could only find the picture! $\endgroup$
    – Bageletas
    Commented Mar 9, 2022 at 7:18
  • $\begingroup$ @Bianfable it's been added thanks! $\endgroup$
    – Bageletas
    Commented Mar 9, 2022 at 7:23
  • 1
    $\begingroup$ I’m really torn between the two answers here. You were first and found a really good picture, and I thank you very much, but in the end I think I need to reward the apparent effort put in by @mast. $\endgroup$
    – Jim
    Commented Mar 10, 2022 at 7:08
  • 1
    $\begingroup$ @Jim if I could give my extra votes to Mast I would! It's a well researched answer and certainly the better of the 2. Fun topic! $\endgroup$
    – Bageletas
    Commented Mar 10, 2022 at 8:54

Turns out answering whether this is controlled manually or automatically is doable (it's manual). Answering how it's controlled exactly is a lot harder unless you have the datasheet, which I don't. The system used (r-TWR, sometimes written without hyphen as rTWR) is part of Saab's Digital Tower portfolio so if you really want to know, try sending them an e-mail. Meanwhile I'll dump the information I gathered while trying to answer it with a conclusion on what it probably looks like.

To replace about a 100 aging control towers, the FAA is looking for a functional replacement that will:

  • Meet operational and cost requirements
  • Maximize energy efficiency
  • Be easy to modify according to height needs
  • Be rapidly constructed

Source: General Aviation News

That's a lot of buzzwords for indicating it's going to be a complete replacement of the tower and the same system should be able to work on multiple locations with only minor adjustments.

The proposed replacement active on KJYO is also active on KFNL.

Remote tower control room KJYO: Control room KJYO

The rTWR system at Leesburg utilizes high definition video camera, a pan-til-zoom camera, a signal light gun, and microphones to provide data directly to controllers at a remote tower center located at the airport.

Source: GlobalAir

The article linked by Bageletas here (link) shows the cameras and sensors enable object tracking and anomaly warning. With the picture of the signal light gun, the following title is shown:

A signal light gun provides a backup if the system is faulty.

It's a backup system. None of the systems I've seen speak about any automation in a signal light gun. For example, the competition by Silent Sentinel has the Jaegar and Osiris, both mentioning they're capable of 'supporting additional specialist technologies including the signal light gun'. Which still doesn't tell us whether they can do it themselves or that they can support such a system when other parts are added.

The FAA doesn't speak about it either. The only functions of a Remote Tower Center (RTC) that mention a light gun are SLG and RLG.

Provides capability to communicate with aircraft, vehicles, equipment, and personnel on the airfield and surrounding airspace through visible light visual signals.

Remote control signal light gun capable of being directed in azimuth and elevation to cover backup communication with aircraft, vehicles, and personnel in areas of jurisdiction.

The SLG must [R0184] provide the capability of transmitting signals in accordance with FAA Order 7110.65, 3-2-1, Light Signals.
The SLG function must [R0016] be capable of being verified for proper operation by the ATCS.
Note: Proper operation consists of the ability to direct and transmit the intended signal.
The SLG must [R0203] be capable of being directed at a target of interest.
The SLG function shall [R0204] respond within 250 milliseconds of operator input.
The SLG functionality shall [R0205] be capable of reaching a continuous rotational speed of at least 60 degrees per second.
The SLG functionality shall [R0206] be capable of reaching a continuous tilting speed of at least 60 degrees per second.
The SLG functionality shall [R0208] provide the capability of movement between two positions in the horizontal plane which are 60 degrees apart from a resting state to a resting state within 2 seconds, not including control latency.
The SLG functionality shall [R0255] provide the capability of movement between two tilt positions which are 60 degrees apart from a resting state to a resting state within 2 seconds, not including SLG functionality control latency.
The SLG must [R0015] be capable of being disabled in Maintenance mode.

Note: The user control includes interfacing with all the elements of the RT system necessary for the ATCS to fulfill their mission. Elements include RVP, SLG, Binocular Function, SVP, AAA, ancillary devices, audible and visual alerting, etc. Layout and design of control device(s), information display(s), and alerting methods need to provide a suitable human-machine interface design to minimize human error and maximize efficiency.

Source: FAA, remote tower systems requirements

So while the system itself is perfectly capable of tracking multiple aircraft, the FAA doesn't require the SLG to perform this function in an automated tracking capacity. The SLG must be capable of being directed and manually doing so is fine.

Considering the rest of the required functionality, a joystick might be part of the system but that would include a piece of hardware just for that task. From what I've read, the pictures that are shown and the experience Saab has with related systems (like I-ATS), I can say with relative confidence that the systems are primarily controlled by multi-touch screens or screen, mouse and keyboard.

These systems usually don't provide more functionality than required, even if they're capable. It's possible automated tracking will be added later as a feature, but that's a lot of work for a backup system. For now, it is manually controlled.

Note: I have no affiliation with either of the parties mentioned, although I have worked in the past for a company producing equipment for I-ATS.


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