Air traffic control exists for one reason; to facilitate the safe and expeditious flow of air traffic. As has been discussed in our article here, air traffic controllers work in three different environments; tower, approach, and enroute.
Right, so we know air traffic controllers work at airports but do they work at every airport?
Not all airports have ATC service. At most major airports, there is an ATC service 24/7, which will often be regulated by the country’s aviation or transport authority. However, smaller facilities like regional airports and aerodromes may only have an ATC service during the day, while others may have none at all.
Why do some airports have ATC service and some not? Is it unsafe to have uncontrolled airports and airfields? Let’s open up the discussion!
Table of Contents
Types of air traffic (and number of movements)
Airports and airfields are used for a wide variety of services; regular public transport (RPT), charters, freight, flight training, and military services are just the common ones.
These services dictate the aircraft types that will use the airport. It’s safe to assume that a small airfield with a grass landing strip probably won’t expect traffic as big as a Boeing 737.
These smaller airfields are utilized by equally small aircraft that are flown for general aviation purposes, and are not often used for lots of RPT movements.
The busier the aerodrome or airport, the greater the need for an ATC service.
Most of the world’s international and busy domestic airports have a full air traffic control service that controls every single movement at the airport; from the ramp, along taxiways, and onto the runway, for every departure and arrival.
This is certainly true of the airports you and I are familiar with and using on a regular basis
Military airports almost always have an ATC service. It may not be 24/7, but during the day when military pilots are conducting training and exercises, the pilots will be controlled more or less from the tarmac and beyond.
Busy regional aerodromes will often have an ATC service, and that is probably dictated by the country’s transport authority if they determine it is too unsafe, or inefficient, to operate without such a service. Flight training, aerial work, parachute operations, charter services, and aviation enthusiasts are the types of flying conducted at smaller facilities, and this amazing mix of pilot experience and aircraft types welcomes a level of ATC intervention.
However, that’s not to say busy regional airports with lots of flight training, for example, are always controlled! It is often not the case, because if an aerodrome does NOT have an ATC service, then it’s one less thing pilots and businesses need to pay for.
It’s no coincidence to see uncontrolled airfields full of flight training schools; it keeps the costs for students down.
5 Reasons Why Some Airports Have No ATC Service!
There are literally thousands of airfields and aerodromes all around the world that do not offer either an ATC service, or a 24/7 ATC service. There a few major points that determine why:
- The number of aircraft movements/traffic frequency. Airfields that are small are likely to have less traffic. Thus, pilots are left on their own to follow procedures and to separate themselves from other traffic.
2. Traffic patterns and curfews. Some airports have operational curfews that limit, or stop altogether, traffic at night. Thus an ATC service may not be necessary (although the major international airports will still staff their towers regardless). There are many airports that are uncontrolled overnight, on weekends, and public holidays, but will have a full ATC service during the week.
3. Location. Seems obvious, but isolated and remote locations can be both unappealing and difficult to live in (this issue is being addressed with the use of remote towers, outlined below). Luckily these locations generally aren’t so busy anyway.
4. Cost. Safety first? Certainly, but it’s with some chagrin that it must be said safety does come at a cost. It’s simply unfeasible and uneconomical to provide an expensive ATC service, with all its systems and regulations, at every airfield. ATC authorities always assess the needs of airports and determine if an ATC service is required. Likewise, they may close a tower if traffic or the types of services change.
5. Staffing. There are few ATC authorities that could honesty admit they have the required ATC staff for the services they have to offer already. The need to staff even more towers is an impossible consideration.
Safe Operations at Uncontrolled Aerodromes
Just because an airfield or aerodrome is uncontrolled does not mean pilots can simply do as they please. There are strict procedures and regulations in place to ensure the safety of all movements, from the weather conditions that are allowed for flight, to the broadcasts pilots are required to make, and the routes flown.
It’s been mentioned before, but standardizing procedures helps ensure safe operations; if everyone is on the same page and has the same understanding of what’s going on, accidents are less likely to happen.
How do Pilots Communicate at Uncontrolled Airports?
Uncontrolled airports have a CTAF- Common Traffic Advisory Frequency, on which pilots will monitor and make their transmissions, and detailing their intentions so other pilots are made aware. Pilots should broadcast the following;
- Callsign/registration
- Flight rules (IFR or VFR)
- Aircraft type
- Departure and destination aerodromes (yes, they really do have to confirm where they are departing from, as there will be traffic monitoring that might be overflying or departing from a nearby site)
- Taxi and departure intentions (which taxiway and which departure route, if the plan is for air work in the circuit, and so on). The pilots might also advise POB, though this information is normally broadcast directly to ATC, on the appropriate ATC frequency.
Likewise, when aircraft are inbound they will change to the airport’s frequency and make a broadcast for traffic monitoring, additionally advising their estimated time of arrival (ETA), intended approach, and runway for arrival.
The Risks of Uncontrolled Aerodromes
It seems obvious to say it, but unfortunately, safety will be compromised at airfields and aerodromes that do not have an ATC service. Pilots are responsible for following the correct procedures but mistakes, and therefore accidents, can happen. It might be a case of a pilot attempting to land with an aircraft already on the runway about to depart, or confusion about the location of traffic in the circuit around the airfield.
Combine these issues with factors like inexperience, poor weather, a wide mix of aircraft types, and it is easy to see how incidents occur.
Thankfully, aviation is full of professionals and the fact is that, despite the inherent risks, flying is still incredibly safe and most pilots are to be commended for educating themselves on the relevant procedures and regulations.
Remote and Virtual Towers
Remote towers are a relatively new concept (development began in 2002) but the benefits are worthwhile. An ATC service is conducted away from the airport being controlled with the use of cameras and primary radar and surface movement radar.
Europe has pioneered the concept but countries like the USA and Australia see great potential in utilizing them as well, to assist in providing ATC services at locations that are isolated, and consolidating services together for many quieter aerodromes (for example, an air traffic controller could be licensed to control at two different towers on other sides of the country from one another, an idea that was almost unthinkable just a couple of decades ago).
In 2015, Sweden was the very first country in the world to open a remote tower for Örnsköldsvik Airport; its ATC services are conducted from Sundsvall–Timrå Airport, some 130km away.
Germany has already built a remote tower centre in Leipzig, and plans to relocate the services for many of its smaller airports there. There are vastly more benefits that will be detailed in another article.
Exceptions: When ATC service becomes unavailable
In March 2020, during the COVID-19 outbreak, Las Vegas McCarran Airport (KLAS) had to stop its ATC service due to an air traffic controller testing positive for coronavirus. However, instead of the airport closing, it remained open by becoming a CTAF, and plane spotters have been treated to the rare sight of passenger jet aircraft sorting out their own sequences and departures and arrivals without the use of ATC.
Australia is a big country, and before the COVID-19 outbreak, much of it was made accessible thanks to the aviation industry serving various regional and remote towns.
There are dozens of uncontrolled airports that facilitate RPT traffic without an ATC service. 737s and Dash-8 Q400s are mixing it up with little Cessnas, Pipers, and helicopters in the circuit, and all the pilots are responsible for their own separation once the aircraft has been given a call from ATC, “Cleared to leave controlled airspace descending…”
Conclusion
The short answer to all this is not all airports offer an ATC service, but the why is the really interesting point. For the vast majority of people flying, they’ll never know anything different than a flight that is controlled from push-back to arrival, but a few flying to more interesting locations won’t even be aware that a portion of their flight was done without being under the watchful eye of ATC. It’s worth remembering it’s still a big world out there, and a lot of freedom is still available.
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