Air Traffic Control - The game with no pause button

Blog

The air traffic control business is something special. ANSPs operate behind closed doors and ATCOs are regarded as a special kind of talented people. The biggest reward of becoming an Air Traffic Controller is the self-consciousness of exercising a profession that keeps aviation safe. There's an old motto very popular among aviation professionals that says: ”if you think safety is expensive, try an accident”.

Safety is always priority number one and nothing can be considered too expensive to maintain it. Safety simply comes first.

For decades, there was no competition and the old state-owned organisations were running quietly in their corner of the world. Those times are now gone. Economic pressure, international regulations and a lot of attention from the airlines put ATC under scrutiny. A new kind of managers coming from other industries also join the game and want to apply rules and methods from their professions.

Enforcing new practices on people who consider themselves special and often set very high standards for themselves is not an easy task. It can generate a lot of resistance. Sometimes not without reason… But is ATC really that different?

From a high-level perspective, the game of air traffic management consists of letting the largest possible amount of traffic flow through a constrained network. Some of the constraints come from users, others from technology and others from the people operating the network. History plays an important role here, as does the dispatch of investments between network users and operators. To name just one example, switching to new communication systems more capable than the good old VHF would be expensive for ANSPs but even more for airlines. Users would not adapt to change without a solid business case and clear benefits.

It is common to hear comparison with the application of traffic management in other sectors, even more from people coming from other industries. Examples from the car industry range from traffic lights to self-driving cars. High-speed trains run at intervals sometimes below one minute and metro lines operate without human intervention, at least not locally in the train. This would not be possible without automation and bringing this kind of automation to air transport is an honourable wish.

But is the “traffic flow through a network” comparison really appropriate? Largely, yes. But, and this is not a small but, a lot of care must be given to degraded modes and fallback plans. Supporting pilots and ATCOs with automation and removing technical hurdles helps improving the network capacity. If an ATCO can handle 30% more traffic with some automation, why not to use it? Autopilots and flight management systems relieve pilots from an important part of their workload and there is no reason why conflict detection and optimization systems shall not do the same for air traffic controllers.

But the main difference with trains and cars is that there is no pause button for ATC. When everything goes wrong, there is no easy escape like turning all traffic lights to red, having all trains stop where they are or all self-driving cars stopping on the emergency lane. When automation fails in an airline cockpit, the crew has to revert to basic flying and navigation skills, at the price of an enormous workload increase.

When technology fails at an airport, aircraft on the ground remain on the ground. The ones established on final approach will probably land within minutes and then everything is safe again. But for departures and en-route flights, it takes more time to get to a safe status. If an en-route control center fails, it will warn its neighbors and will stop accepting all incoming traffic. But what about the flights which are there at the time at which failure occurs? It is not possible to have them all hold or to just rely on TCAS.

If automation allows an ATCO to handle 30% more traffic, what happens when this automation fails? The likelihood is slim to none, but it will happen. Shall a fallback system allow for the same capacity? Or are 60% enough when operating on the fallback system? If yes, how to come down safely from 100% to 60%? With extra staff members on site, “just in case”?

Another interesting question to ask is what the role of the fallback system is. Is it to evacuate all traffic and close the airspace or is it to operate at reduced capacity until the main system is back? How safe is it to work using the fallback system, knowing that there is then no further degraded mode available shall the fallback system fail too?

When the customers that you move around trust you with their lives, stopping everything is a good plan B but it is only an option if you are on the ground. There is no pause button in the air and this is why ATC people are used to think beyond a single failure and include expensive and sometimes complex systems in their plans.

Reducing complexity, removing technical hurdles, integrate modern technologies and streamlining the operations to improve the network capacity are all good things. There are many lessons that ATC can learn from other industries and the fresh, innovative approaches brought by people coming from the outside world should not be turned down just because “ATC does it better”. But fresh and innovative shall not be just one-to-one copies from other industries where the plan B is just to stop everything and fix the problems.

Not having a “pause” button does not mean that you can’t profit from technologies that have proven successful in other industries. But it must be done “in the ATC way”. The biggest challenge for those bringing such innovations to ATC is to find this middle way, which is also the only one towards more efficient, modern, innovative, economical and safe ATC. Because safety will always come first.