What’s the Difference Between Tower, Information and Radio?
Updated: 4 days ago
You arrive on final at one airfield and hear “cleared to land”. At another, the reply is “land at your discretion”. At a third, you receive the wind and a report of another aircraft. The runway ahead may look much the same, but the decision you make after that transmission depends on the service being provided.
The last word in an aerodrome's callsign gives you that first clue. Tower means Air Traffic Control, Information means an Aerodrome Flight Information Service, and Radio means an Air/Ground Communication Service. Understanding the authority behind each voice helps you avoid waiting for a clearance that will never come, or moving when you still need permission.
Contents
Tower: clearances and instructions
An aerodrome controller can issue clearances and instructions to aircraft on the ground and in the air within the applicable area of operation. You might receive a taxi route with a holding point as its limit, an instruction about how to join the circuit, or a clearance to land.
Those messages authorise specific actions. A taxi instruction to a runway holding point gets you to that holding point. Entering the runway requires the appropriate further permission. A circuit join instruction also leaves a separate decision ahead: you need a landing clearance before landing.
Read back the items that require it, including the runway and landing clearance. If a transmission is unclear, ask for it again before acting. A guessed holding point is a particularly expensive way to save a few seconds on the radio.
ATC also provides traffic information and can organise the landing order. Keep looking outside and assess whether you can safely comply with an instruction. You remain responsible for the aircraft, including deciding whether the crosswind is manageable. Tell the controller promptly if you are unable to comply.
Information: taxi instructions, then pilot decisions
At an aerodrome using the suffix Information, you are speaking to an Aerodrome Flight Information Service Officer, often shortened to AFISO. The service supplies information that helps you operate safely at the aerodrome and within its Aerodrome Traffic Zone, or ATZ.
There is an important ground-movement distinction in the UK. AFISOs can issue instructions for defined movements on the apron and manoeuvring area. For an aeroplane departing along a taxiway, that includes taxi instructions up to the runway holding point, and an instruction to hold there. Treat the holding point as a real limit while you wait for the next exchange.
Runway operations need closer attention. An AFISO supplies information to help you decide whether it is safe to line up and take off. Runway crossings by taxiing traffic are a specific ground-movement situation in which instructions can be given. After landing, taxi instructions can apply again in the appropriate ground area. The boundary depends on the movement being made, so learn the local procedure with your instructor.
For the light-aeroplane circuit examples here, the AFISO provides information to airborne pilots. Requests such as “report final” help build the traffic picture. The pilot decides how to integrate safely with the circuit, using that information and the published procedures. Helicopter air-taxi and hover operations have additional specific phraseology and are outside these examples.
When you hear “land at your discretion”, assess the runway and decide whether to land or go around. That phrase is not an ATC landing clearance. The AFISO should only pass it when the runway is unobstructed, but a new hazard can appear afterwards. Your view through the windscreen still counts.
Reply with your intention, such as “landing runway two seven”. There is no need to add “at my discretion” to your answer. A clear statement of what you will do helps everyone following the exchange.
Radio: information that supports your own judgement
An Air/Ground Communication Service, or AGCS, uses the suffix Radio. Its operator can pass useful aerodrome information, including weather and reported traffic. AGCS is not an air traffic control service, and the operator cannot originate taxi instructions or take-off and landing clearances.
Traffic information may come from other pilots' reports. The operator is not required to have a continuous view of the movement area or the surrounding airspace, so an empty frequency and a report of no known traffic still leave you with lookout work to do.
Make useful position calls and announce your intentions. Listen for aircraft whose position affects your plan, then check that the manoeuvre is safe before carrying it out. The other aircraft may be a small shape against a line of trees long before it becomes an obvious problem on final.
This also explains why an Air/Ground operator should not say “land at your discretion”: that expression belongs to AFIS phraseology. At a Radio aerodrome, expect information and make your own landing decision in accordance with the rules and local procedures.
The operator can still pass an urgent warning about a hazard. A vehicle on the runway needs your immediate attention whichever service is speaking. A timely warning gives you the opportunity to act before the situation becomes dangerous.
The same taxi situation at three aerodromes
Imagine three fictional aerodromes: Brookfield Tower, Merefield Information and Hillfield Radio. Each has runway 27 in use, the same taxiway to holding point Alpha, and QNH 1016. You are in G-ABCD on the apron and want to depart. At each site you have already checked the published procedures and obtained any required permission to use the aerodrome.
At Brookfield, you request taxi. The controller tells G-ABCD to taxi to holding point Alpha for runway two seven and gives QNH one zero one six. You read back the taxi instruction and pressure setting, then follow the route to its limit. If you are told to hold position because another aircraft is approaching, you remain there.
At Merefield, you also request taxi. The AFISO can give the same taxi instruction to Alpha and can tell you to hold position at that holding point. The similarity is useful: both exchanges give you a defined taxi limit. At the next stage, Merefield will use information and the appropriate discretion phraseology for departure, leaving you responsible for deciding when the take-off is safe.
At Hillfield, you request aerodrome information for departure. The operator gives you runway two seven, QNH one zero one six and any relevant reported traffic. You announce that you are taxiing to Alpha and assess the movement yourself under the aerodrome's permission arrangements. The authority to taxi comes from those permission arrangements, with the radio information supporting your decision.
At all three sites, a hold-position readback needs to convey that you are holding. At Tower or Information, respond to the instruction with “holding” and your callsign. At Radio, if the traffic information makes waiting the safe choice, announce that intention so other pilots can understand what is happening.
The useful preparation exercise is to speak the whole sequence aloud, including the decision at the hold. QuizAero Bitesize links Communications with Air Law and ATC Procedures, so you can study what an exchange permits as well as the words you need to say.
The same final approach, with different replies
Now put G-ABCD on final for runway 27 at each fictional aerodrome. The preceding aircraft has vacated and the reported surface wind is 270 degrees at eight knots. Assume the earlier joining and circuit exchanges have already taken place.
At Brookfield Tower, the controller can clear you to land. You read back the runway and clearance, continue assessing the approach, and land if it remains safe. If that clearance has not arrived, ask while you have time to resolve it. Seeing a clear runway does not supply the missing clearance.
At Merefield Information, the AFISO uses “land at your discretion”, with the runway and surface wind. You respond with your landing intention, check that the runway remains available and continue only while the approach is safe. If the preceding aircraft is still on the runway, the AFISO provides that information and you assess the need to go around.
At Hillfield Radio, the operator may pass the wind and report that the preceding aircraft has vacated. You announce your intention to land and check for yourself that the landing can be completed safely. Waiting for “cleared to land” here would mean waiting for a transmission the operator has no authority to originate.
Across those three approaches, the aeroplane ahead is the same and the wind is the same. The service changes the authority of the radio reply. Keep that distinction in mind before the workload rises on final, when searching for the right words can steal attention from the right view.
ATZ entry and aerodrome permission
The service distinction also affects entry into an ATZ during the notified hours when Rule 11 applies. At an ATC aerodrome you need the unit's permission. At an AFIS or Air/Ground aerodrome, you must obtain the information needed to conduct the flight safely within the zone. With radio fitted, report your position and height on entering and immediately before leaving it.
Getting a callsign acknowledgement alone can leave that requirement unfinished. Allow time to obtain the relevant information before reaching the boundary. If you cannot establish the required exchange, resolve the situation outside the ATZ while maintaining a safe flight path.
Permission to use the aerodrome is another consideration. Prior Permission Required, or PPR, arrangements can apply regardless of the radio service. At an uncontrolled aerodrome, taxi permission comes from the person in charge or the notified on-watch flight information service. Follow the operator's arrangements at a Radio aerodrome. An operator can also restrict or close its aerodrome, and that message may be relayed over the radio.
An AFISO or Air/Ground operator can relay a clearance issued by an ATC unit elsewhere, with the originating authority identified. Listen to who issued it. The named ATC unit is the authority behind that clearance, while the local station continues to provide its own service.
Brief the service before you need it
Before visiting an unfamiliar aerodrome, check the current service and its hours, alongside the joining and ground procedures. Build the suffix into your briefing: which instructions can this station give, and which decisions will you make using its information? This comparison concerns aerodrome services; London Information is an en-route service with a different role.
Practise the transition with your instructor if your training has mainly taken place under one service. A familiar voice on your home frequency can make radio work feel automatic. An unfamiliar suffix asks you to think about the meaning of the reply as well as its wording.
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