FRTOL01The Four UK Flight Information Services
Outside controlled airspace, the UK offers four air traffic services, set out by the CAA in CAP 774. They differ in how much help you get with other traffic, but one rule runs through all of them: you remain responsible for collision avoidance and terrain clearance.
Basic Service
Information useful for the flight. No one is required to monitor you, and avoiding traffic is all yours.Traffic Service
Basic Service plus specific radar-derived traffic information. No deconfliction.Deconfliction Service
Traffic information plus headings or levels intended to keep set distances from other traffic.Procedural Service
Deconfliction only from other aircraft on the same Procedural Service. Nothing on unknown traffic.None is compulsory in class G airspace. You choose the service that suits the flight, and ask for it. Our main guide also has a short summary of the four UK flight information services.
02Basic Service
The default service for most VFR flying, and the only one a flight information service officer (FISO) can give.
Under a Basic Service you get advice and information such as weather, changes to facilities, aerodrome conditions and general airspace activity. Both controllers and FISOs provide it. That's why calls to London Information always end in a Basic Service.
- No routine traffic information. You may hear general warnings, like gliding at a named site, and you'll get a warning if they see a definite risk of collision. Don't rely on either.
- No one has to watch you. A controller may use radar, may give you a squawk and may even identify you without saying so. None of that upgrades the service.
- You fly your own way. You can change heading or level without telling anyone, unless you've made an agreement with a controller to hold a level or route.
- Terrain is your problem at all times.
03Traffic Service
A surveillance-based service from an air traffic controller with radar. It's the most a VFR pilot can ask for outside controlled airspace.
On top of a Basic Service, the controller passes specific traffic information on aircraft that look relevant to you. CAP 774 describes relevant traffic as aircraft expected to pass within about 3 NM and, where its level is known, 3,000 ft, and asks controllers to aim to warn you before it is within 5 NM. Many LARS units offer it.
- You must be identified first, and the controller tells you when you are.
- No deconfliction. The controller may give headings or levels for positioning or sequencing, but isn't trying to keep you a set distance from anyone. Seeing and avoiding is still your job.
- Tell them before you change. Under your own navigation you can alter course, but don't change your general route or area without advising the controller and getting a reply. Don't change level or level band without telling the controller and getting a reply, whether you chose the level or ATC gave it. On a heading from ATC, don't change heading without doing the same.
- If an instruction would take you into cloud and you aren't qualified, say so and ask for something else.
Acknowledge traffic information with "roger" until you see it, then say "traffic in sight", or "traffic not sighted" if asked.
04Deconfliction and Procedural Service
Both are for flights under IFR only. A VFR PPL student shouldn't ask for either, but you need to know what they are for the written exam.
Deconfliction Service
A radar controller gives traffic information plus headings and/or levels aimed at keeping you a planned distance from other traffic. Against uncoordinated traffic, CAP 774 sets those minima at 5 NM laterally or 3,000 ft vertically (3 NM or 1,000 ft against aircraft the controller is working or has coordinated). You're expected to accept headings and levels that may put you in cloud, which is why CAP 774 tells VFR pilots to ask for a Basic or Traffic Service instead. If you choose not to follow the advice, you must say so, and you take on responsibility for avoiding that aircraft. Ultimately, avoiding other traffic is still the pilot's responsibility.
Procedural Service
Given by an approved ATC unit, usually without radar, typically to IFR flights holding, approaching or departing. The controller uses levels, radials, routes, times and your position reports to keep you apart from other aircraft on the same Procedural Service. It says nothing about unknown traffic, so you may meet aircraft with no warning at all.
05The Four Services Side by Side
| Service | Given by | Radar | Traffic information | Deconfliction | Flight rules |
|---|---|---|---|---|---|
| Basic | Controller or FISO | Not required | General warnings at most | None | VFR or IFR |
| Traffic | Controller | Required | Specific, on relevant traffic | None | VFR or IFR |
| Deconfliction | Controller | Required | Specific, with avoiding advice | Headings and levels to set minima | IFR only |
| Procedural | Approved ATC unit | Not required | On known traffic only | Against other Procedural Service traffic only | IFR only |
Under every service, collision avoidance and terrain clearance stay with the pilot, and an alerting service comes with all four.
06Requesting, Upgrading and Changing a Service
Ask for the service by name on your first call. The controller must agree it, and you read the service type back. CAP 774 treats that exchange as an agreement: both sides then stick to that service's rules.
Requesting a Traffic Service
This example uses the fictional radar unit Wrayton Radar. The squawk and pressure setting are made up.
Wrayton Radar, Golf Juliett Juliett Echo Romeo, request Traffic Service.
Golf Juliett Juliett Echo Romeo, Wrayton Radar, pass your message.
Golf Juliett Juliett Echo Romeo, PA-28, local flight from Newbridge, six miles west of Hillford, altitude two thousand fower hundred feet, Cotswold one zero zero niner, VFR, routeing to Hillford.
Golf Echo Romeo, squawk fower tree six one.
Squawk fower tree six one, Golf Echo Romeo.
Golf Echo Romeo, identified fife miles west of Hillford, Traffic Service.
Traffic Service, Golf Echo Romeo.
Neither the squawk nor "identified" is the service. Only the words "Traffic Service", read back, start it.
Traffic Information
Golf Echo Romeo, traffic ten o'clock, fower miles, crossing left to right ahead, indicating fife hundred feet above, slow moving.
Roger, Golf Echo Romeo.
Golf Echo Romeo, traffic in sight.
Reduced Traffic Information
When workload, busy airspace, clutter or the edge of radar cover limits what the controller can see or say, they tell you, with the reason and how long it may last. It's information, so "roger" is enough, but treat it as a cue to sharpen your lookout.
Golf Echo Romeo, reduced traffic information from the south for the next eight miles due to the limits of surveillance coverage.
Roger, Golf Echo Romeo.
When the Service Changes
A controller may have to drop you to a Basic Service, for example when you leave radar cover or workload rises. You can also ask to change, for instance before you leave the frequency. Either way, read back the new service.
Golf Echo Romeo, due to controller workload, Basic Service.
Basic Service, Golf Echo Romeo.
A Traffic Service from a LARS unit often comes with a MATZ crossing too. Our guide to MATZ and ATZ radio calls shows that exchange.
07Common Mistakes
- Thinking a Traffic Service keeps you apart from other aircraft. It doesn't. It tells you about traffic, and you avoid it.
- Asking a FISO for a Traffic Service. "Information" can only give a Basic Service.
- Asking for a Deconfliction Service when VFR. It's IFR only.
- Not reading back the service, or reading back only the squawk.
- Assuming a squawk means you're identified, or that being identified means you have a service.
- Changing route or level under a Traffic Service without telling the controller.
- Saying "roger" to a question, like "confirm you are VFR", when the answer should be "affirm".
08How It Comes Up in the Practical Test
In the FRTOL practical test, the examiner listens for you to ask for an appropriate service by name, give a well-ordered "pass your message" reply, and read back the service type every time it's given or changed.
A Traffic Service request, traffic information to acknowledge, or a change of service partway through are all realistic tasks. The definitions also come up in the FRTOL written exam, so know which services are IFR only and who stays responsible for avoiding traffic. For the phrases themselves, see our CAP 413 phraseology guide. If your radio dies while under a service, our radio failure procedure guide covers what to do, and our overhead join radio calls guide takes you into the circuit at the end.
09Flight Information Service Questions
What is the difference between a Basic Service and a Traffic Service?
A Basic Service gives you information such as weather and airspace activity, and nobody is required to watch your flight. A Traffic Service adds specific, radar-derived traffic information on aircraft that look relevant to you. Under both, avoiding other traffic is your responsibility.
Can a VFR pilot ask for a Deconfliction Service?
No. CAP 774 says a Deconfliction Service is only for flights under IFR outside controlled airspace. A VFR pilot should ask for a Basic Service or a Traffic Service.
Does being identified mean I am getting a radar service?
Not by itself. Identification is not a service. You only have a Traffic Service or Deconfliction Service once the controller says so and you have read it back. Under a Basic Service a controller may identify you without telling you.
Do I need to read back the type of service?
Yes. The type of service is on the CAP 413 list of items that must be read back. End the read-back with your callsign. Reading it back confirms that you and the controller agree on what you are getting.
Can the controller change my service without me asking?
Yes. Workload, radar coverage or terrain may mean the controller has to reduce the traffic information or offer a different service. They should tell you, and you read back the new service.
10Official Sources
This guide is a summary. For real flying, always use the current official documents.
This guide and the FRTOL app aren't approved by or affiliated with the UK CAA, and they don't replace your instructor, your examiner or the official documents. Checked against CAP 774 (edition 4) and CAP 413 (edition 24) in November 2026.