Overnight on Friday 22nd January 2021, NATS successfully transitioned London City Airport's air traffic operation to the new Digital Tower at its Swanwick control centre.
Today, the controllers are managing flights 115km away from the airport in what is a first for a major UK airport.
Preparing to transition London City to the UK’s first major digital control tower was a huge technical and engineering undertaking, but also a very human one. From training the Air Traffic Controllers on new equipment, to supporting their relocation to the south coast, the project was no mean feat. This is the inside story…
What is a Digital Tower?
First things first. What is a 'Digital Tower'? It's a term that can mean different things, but essentially it involves using a combination of camera technology and screens to replicate or augment the air traffic control service. For London City Airport that involves taking the visual images from 16 cameras at the airport and sending them to a bespoke operations room at NATS' Swanwick air traffic control centre in Hampshire.
Conducting an Engineering Orchestra
The journey began in 2017, when the airport started out on its wider redevelopment plan. A new taxiway and aircraft stands would make visibility difficult from the airport’s original 18 metre high control tower, and with airside space at a premium, NATS suggested a digital alternative, something that the airport embraced with enthusiasm.
From an engineering perspective, the move presented a different set of challenges with many moving parts. The crux of the project was to ensure all the air traffic systems that existed in the old tower – from radar and flight data to voice communications – could be accessible 115km away in Swanwick, with the addition of high definition real-time images from a new 50 metre high camera mast.
All that data had to be provided safely and securely and with a latency of less than a second, whilst ensuring resilience and contingency measures were baked into the project from the start.
The move to a digital tower has presented a different set of challenges, with so many moving parts; alongside we’ve had to add training and reskilling into the mix, while dancing around Covid-19 and the challenges of airport restrictions.
Stuart Jackson, System Engineering Manager, London City Digital Tower Project
Voice Communications
Quality voice communications is vital to the safe and efficient running of any air traffic service, so a new Voice Communication and Control System was chosen as part of the transition.
The introduction of this new system followed more than two years of development by the NATS engineering team and was installed alongside other essential voice systems, including the Emergency Voice Communications System and radio - both VHF and UHF - recorders.
Meteorological and Navigational Aid Systems
Weather plays a huge role in air traffic control and the team worked closely with the UK Met Office to assess the quality of METARs (weather information reports) generated from the digital tower images and any potential impact on the production of the Terminal Aerodrome Forecasts - vital information for pilots.
To their delight, what the team discovered was in many cases, the enhanced tools and optimisations of the digital tower showed how this was easier to do than in a conventional tower.
The engineering team also worked with the airport to deliver a new Instrument Landing System and Instrumented Runway Visual Range replacements.
The Mast
London City's digital tower uses multiple independent and private high-speed fibre optic connections to connect the mast to the operations room at Swanwick.
The NATS onsite engineering team at the airport installed hundreds of miles of cables, cleaned camera housings, moved aerials, added lightning protection and adjusted cameras to ensure a picture perfect transition.
Training & Preparation
With the technology journey underway, it was time to help make sure the people were ready too.
While the digital tower technology has been tried and tested at several smaller airports, it had not previously been deployed at an airport of the scale and complexity of London City.
Configuring the new technology to be just right for the airport and the controllers, while extending control of new and existing airport systems down to Swanwick, was critical alongside giving the controllers every chance to become familiar and confident with the change.
The NATS team developed a specific training package so the controllers would be introduced to the digital tower gradually, building on the information each time. This starting with videos and pictures, a Swanwick unit visit, distance learning, before moving onto practical training and then finally, refresher training ahead of the transition itself.
NATS wasn’t changing the way in which the controllers would manage or control the traffic – it would essentially remain a visual job – but it was changing just about everything else. The environment, the equipment, and how the controllers saw the traffic. The latter was probably the most difficult aspect to adapt to. Not only was the perspective changing from an 18 metre high tower to a 50 metre one, the picture in the digital tower shows a 360 degree view compressed into 225 degrees.
That’s actually helpful in terms of improving situational awareness – especially as you can also overlay the images with radar labels and other operational data – but it was still an odd thing to see initially. In practice, the team found the controllers got used to it very quickly, but NATS had to be sure they weren't creating any new, unseen pitfalls.
Ultimately, the training was designed with safety in mind so the team could look forward to the transition with anticipation and confidence.
Human Performance
Air traffic control performance isn’t just about having the right kit; it’s about ensuring each controller feels able to work at their best in an environment that facilitates peak performance.
NATS employs some of the world’s leading Occupational Psychologists and Human Factor Specialists with a deep understanding of human behaviour, the science that sits behind it, and how that can be applied to the safety and efficiency of air traffic control.
When it came to the digital tower, everything revolved around designing an environment – both mental and physical – that would allow the controllers to perform at their best.
NATS' Human Performance team spent hours speaking with each controller to understand their stories and what could improve their transition experience.
The 'sensory' experience I the digital tower is very different to actually being at the airport, and many controllers said being able to hear engines starting or stopping was an almost unconscious cue, so NATS decided to have airfield noise piped in live to recreate that as closely as possible.
Fatigue Management is a huge part of what the Human Performance team do, and we all know how tiring staring at screens can be on the eyes. So it was decided to paint the digital tower walls with different shades of yellow and green with the view it would mitigate the impact of 'blue light' from the panoramic screens.
The desk based equipment was also positioned very specifically so the area the controllers have to scan is much smaller, allowing them assimilate information more easily.
Transition
As you’d expect, a lot of planning went into the transition itself, but delivering it during a worldwide pandemic threw up some unique challenges. The plans had to adapt to take into account access restrictions and social distancing requirements, but in the end it all went extremely well.
The last departure from the old tower at London City was cleared for take-off on a Friday evening and the team opened up on the Saturday morning from Swanwick. Multiple checks were carried out during the night, with several ‘go/no-go’ decision points should it be necessary to revert – but to anyone watching from the outside it was totally seamless.
The team has been controlling from the digital tower for a few months now. It has been a huge team effort from across NATS, the airport and the project's technology partners to get this stage in what has been a little piece of aviation history.