Remote control: the remote tower concept

The world's first-ever remote tower (r-TWR) air traffic control system is poised to go into operation, marking a major industry first for Saab and LFV, Sweden's ANSP. This is the fruit of more than eight years of development by the joint-venture partners.

The system, linking Örnsköldsvik Airport to a remote tower centre (RTC) at Sundsvall, passed Single European Sky ATM Research (SESAR) site acceptance testing (SAT) in February 2013, before entering formal certification testing in mid-2013. With this process ending in December 2013, it only remains for the final report to be issued. The Swedish Transport Agency aims to grant the licence for operations in January 2014.

"Örnsköldsvik will be the first airport in the world to be controlled from a distance. We see this as contributing to flight safety and accessibility for remote regions around the world," says Carl Selling, communications director at LFV.

Using Saab's r-TWR technology, one or more local towers can be operated from an RTC at another location irrespective of distance. High-resolution digital video cameras, metrological sensors, microphones and other devices at the remote airport are linked in real time to the RTC where images are projected onto panoramic LCD screens that can provide a complete 360° view; rather than looking through the window at the aircraft, air traffic controllers view them on the screen.

Controllers at the RTC have complete control over all sensors, lighting, alarms and other tower systems at the remote airfield, along with integrated flight data, electronic flight progress strips (e-strip) and other surveillance and air traffic management (ATM) tools such as advanced surface movement guidance and control system (A-SMGCS), arrival manager (AMAN) and departure manager (DMAN).

All video footage can be recorded and stored for any future need for analysis. In running operations, the controllers manage air traffic as they would in a normal tower, with the remote control process completely transparent to pilots.

"Speaking as a pilot, I can be sure there are no issues for the pilot in this area," says Per Ahl, marketing manager, Saab ATM. "Today, pilots are dealing with controllers and they have no idea where their office is based, so this is no change at all."

Remote solutions

Enabling airports that may currently only offer aerodrome flight information service (AFIS) to offer full air traffic control, r-TWR's main attractions are lower costs and flexibility. Less expensive than building and staffing a stand-alone control tower, a remote solution can provide an as-required service.

"Remote tower services make operating some airports possible," says Dave Kovarik, director of sales and marketing, Saab ATM. "In some locations, if you had to put a dedicated tower and a dedicated controller in there, it would not be feasible."

This ability to adapt to changing demand suits unmanned airports, and ones with limited hours; airports with low to medium traffic levels. Attractive as a lower-cost replacement for outdated facilities, r-TWR can also be used for contingency services at major airports. According to Selling, feedback from air traffic controllers at the Sundsvall facility has been positive so far.

"One of the main questions was about the man-machine integration," he says. "It has been a successful performance. The people using the technology have been able to use it in a smooth and secure way.

"They have an upgraded technical system, they can work with more modern procedures, and they now have a system that can work in every weather condition," continues Selling. "Even in fog, they can still operate the airport."

To support low visibility and night operations, the R-TWR system employs infrared cameras and image enhancement, while features such as digital map overlays, object tracking and alerting aim to make situational awareness better than standard tower operations.

The image quality needed for remote operations, along with related issues such as depth perception and situational awareness in general, have been prominent discussion points. To address this, the system brings together radar and video on the displays, labelling and tracking objects in real time as well as presenting wind and weather information.

"Situational awareness is an important question that has been thoroughly discussed over the years, here in Sweden," says Ahl. "We are totally satisfied with the depth perception that we have now and with the enhanced operations that you are not able to do even in the ordinary tower."

LFV launched the concept of remote towers with a study in 2005, while its remotely operated tower (ROT) joint venture with Saab kicked-off in 2006. The same year saw an initial RTC installation at Malmö to control operations at Ängelholm Airport, where Saab first demonstrated today's more advanced r-TWR system in 2009.

A critical step was SESAR's delivery of the operational service and environment description for remote tower facilities in 2011, which provide the basis for SAT, and LFV were at pains to emphasise that Sundsvall has been subject to exactly the same final certification as any other airport.

More on the horizon

As well as the Sundsvall RTC that will remotely manage operations at Sundsvall Härnösand and Örnsköldsvik Airports, there are three other current pilot projects.

Norwegian ANSP Avinor is testing an RTC at Bodø that remotely manages operations at a heliport at Værøy Airport, a low-traffic site that is served by four scheduled flights daily, and at Roest Airport. Værøy passed SAT in April 2013, while testing continues on the recently installed system at Roest.

Saab is also deploying an r-TWR system for Australia's ANSP Airservices at Alice Springs Airport in central Australia, a project that has been running since 2010.

"Airservices now have their remote tower system installed in Alice Springs and next we will be able to view live data in Adelaide," says Ahl.

During the four-month trial, air traffic controllers over 1,500km away at an RTC at Adelaide Airport will mimic operations at Alice Springs during certain daytime periods. Airservices is looking at possible applications for the technology in the Australian interior and remote north-west.

"If the installation at Sundsvall and Örnsköldsvik is a success, we will have more installations running in Sweden," says Selling. "To be on the front line of this new technology is a huge step for us and we hope to be able to help other air navigation services around the world with it."

With its creaking ATM infrastructure and lack of trained controllers, India has been touted as a prime market for future r-TWR deployment. Its lack of reliable communications networks is a big hurdle, but this is changing with projects such as the National Optical Fibre Network (NOFN) and its ongoing 4G roll-out.

"Interest has been phenomenal," says Ahl. "We will demonstrate the system to potential interested parties in 25 different countries, but it is hard to say who will be the next. We will know more after the next ATC show in Amsterdam."

With line-of-sight views from conventional towers impaired as large airports continue to expand, the use of remote tower technology has broad application well beyond its roots in managing isolated Scandinavian airstrips. Add in other factors such as the expense of upgrading facilities in line with the needs of SESAR and NextGen, and this low-cost approach is something the industry will be hearing a lot more about in future.