Fir, Uir, Cta, Uta??

[Frax]

Most of my work is in US domestic airspace under IFR typically at FL 410 etc. The other day I'm doing a 4 hour flight in "my" business jet in ICAO airspace. I'm PIC.

Obviously I have pen in hand, writing down ETAs and ATAs, watching Mach (within 0.01) and KTAS (within 5%), ready to speak up if I'm to miss a WP by more than 3 minutes, etc. I peruse my charts. With a shock I slowly realise I don't know what all these airspace abbreviations actually mean.

I've been to the ICAO website and its no help. Now I turn to my brothers and sisters at PPRUNE.

Question A: What do the following letters stand for?

FIR = Flight Information Region?
UIR = Upper? [flight] Information Region?
CTA = ConTrol Area?
UTA = Upper [conTrol?] Area?

Question B: What category of airspace are these? A, B, C, D, E F or G?

Question C: What expectations will I have in each of these airspace volumes as to radar service? Is all of it non-radar unless I know otherwise?

Question D: What part of a CTA, if any, is always a UTA?

Question E: What ATC services (i.e. pilot duties) exist in an FIR as distinct from a UIR, CTA, UTA?

In summary: What the dev#l are those letters for? What if anything changes (pilot-controller duties) when you fly from one to another?

Rather embarrassed not to know. Thanks in advance.

[Jerricho]

Whoah..........what a post. Where's Scott, sounds like his department (especially with the States slant!)

The TLA's are there to confuse.

[1261]

If you were flying in the UK, the answers would be:

A. Correct. Not sure about UTA, though!

B. In the UK, the UIR is Class B airspace; the FIR is Class G airspace outside the airway system (Class A) and CTAs/CTRs (Class A at busier airports, Class D elsewhere). This classification is entirely up to the national authorities and varies considerably from state to state, even within the EU.

C. Again, in the UK you'd generally be under a radar control service at larger airfields. In Classes F and G you'd be under a RAS or RIS as appropriate unless it's a non-radar unit. Bottom line is, unless you're under a RCS you should be told on first contact what service is being provided.

D. None in the UK (I think).

E. See answer to C.

Then again, if you fly exclusively in the US it'll be completely different so I'll let Scott (or one of his colleagues) fill you in.

[Frax]

Jerricho and 1261

I've got a handle on US domestic airspace stuff. I'm looking for guidance from fellow PPRUNErs on non US terminology.

US Enroute Control Center (ARTCC, cat A airspace typically) = ICAO FIR?
US Terminal Control Area (TCA, cat B airspace) = ICAO TMA?
US Airport Radar Service Area (ARSA, category C airspace) = ICAO CTA?
US Airport Traffic Area (ATA, Cat D airspace) = ICAO ATZ?

But I do not fully understand the air traffic services available, or to put it from a pilot point of view, I do not fully understand what my obligations are as a pilot. Do I automatically make pos reports? Do I expect radar service? Is the airspace prohibited to VFR aircraft? Are all aircraft in the airspace known to ATC (in theory?)

Thanks already, and thanks in advance, for your answers.

[1261]

Unfortunately there's no simple answer.

If you were flying into Edinburgh, you'd be in Class B at TOD, Class A for a short while until you get to the Scottish TMA, where it's Class D all the way down to the deck (including the Edinburgh CTZ from 6000' down). Oh, and that's if we forget about the short segment of Class E from about thirty miles out to fifteen-or-so!

Bottom line is, you'd always be under a Radar Control Service in a known traffic environment - or will you?

In the UK VFR traffic does not require a clearance (or even to be in two-way contact) from ATC to operate in Class E airspace. Therefore, Classes E, F and G can be an "unknown traffic environment". But if you're IFR you'll still be under a RCS; figure that one out if you can.

The UK tends to base its flight rules on airspace classifiaction, hence it doesn't really matter if you're in the Edinburgh Aerodrome Traffic Zone, Control Zone or the Scottish Terminal Control Area; it's Class D all the way and the rules are the same. The same is true for Heathrow, all the various elements are Class A - so (as far as IFR traffic is concerned) the rules are the same.

[Scott Voigt]

Hi FRAX;

Actually, you can find most of what you are looking for in the AIM as far as the class A,B,C etc... The US has been using that for quite a few years now. As to some of the others and what they mean, when you go to your recurrent, ask the folks at the sim center of your choice for any info that they have on international ops. They should have it in their library. I know at SimuFlite, you can find all of this info...

regards

Scott

[5milesbaby]

A duplicate of my reply in the Tech Forum:-

From the UK Mats Part 1 (Cap493):

Division of Airspace
The United Kingdom airspace is divided into two flight information regions. Within each region the airspace below flight level 245 is known as a lower flight information region (FIR) and that at and above as an upper flight information region (UIR).

---basically in the UK, the airspace above FL245 is Class B, therefore everyone has to have a clearance to enter and thus is known traffic. In many parts of Europe the division is FL195. Inside FIR's, Airways and Advisory routes are established, and in the UIR's these are then Upper Air Routes. An Airway is 10nm wide, extending 5nm either side of the centreline, often (but getting rarer) outside these limits you are outside CAS. In UIR's you are always inside CAS, and if you get over 5nm from the centreline of an Upper Air Route, are only considered to be 'off route' whereby co-ordination with the Military is normally necessary. In the UK there are set times where all a/c will be given on-route status even if off route, normally during the night and at weekends. Not every Airway has an associated Upper Air Route and vice versa.

Classification of Airspace
The classification of the airspace within a flight information region determines the flight rules which apply and the minimum services which are to be provided.

---the classes are A-G, A-D being controlled classes, E/F are advisory areas, and G is totally uncontrolled.

CTA-Control Area
CTR-Control Zone

---CTRs are control zones within defined limits of an aerodrome, and these can be surrounded by CTAs (Control Areas) to link to the Airway network and give added protection if necessary.

In the abbrieviation list there is no mention of UTA.


and also an addition of classes of airspace according to the Mats Part 1:-

2 Classification of Airspace

The classification of the airspace within a flight information region determines the flight rules which apply and the minimum services which are to be provided. These are summarised below.

Class -- Flight Rules -- Aircraft Requirements -- Minimum Services by ATC Unit

Class A -- IFR only -- ATC clearance before entry --Comply with ATC instructions-- Separate all aircraft from each
other

Class B -- IFR and VFR -- ATC clearance before entry--
Comply with ATC instructions--
Separate all aircraft from each
other

Class C --IFR and VFR -- ATC clearance before entry
-- Comply with ATC instructions--

(a) separate IFR flights from other IFR and VFR flights

(b) separate VFR flights from IFR flights

(c) pass traffic information to VFR flights on other VFR flights and give traffic avoidance advice if requested

Class D -- IFR and VFR -- ATC clearance before entry--
Comply with ATC instructions--

(a) separate IFR flights from other IFR flights

(b) pass traffic information to IFR flights on VFR flights and give traffic avoidance advice if requested

(c) pass traffic information to VFR flights on IFR flights and other VFR flights

Class E -- IFR and VFR -- IFR flights to obtain ATC clearance before entry and comply with ATC instructions -- VFR flights do not require clearance--

(a) separate IFR flights from other IFR flights

(b) pass traffic information, as far as practicable, to IFR flights on VFR flights.

(c) VFR flights in contact are to be given traffic information as far as practicable

Class F -- IFR and VFR -- Participating IFR flights are expected to comply with ATC instructions -- Separate participating IFR flights
from each other

Class G -- IFR and VFR -- None -- None



Hope the table is understandable, if not it can be found on the net in the Mats Part 1 (caa.co.uk) and is in Chapter 2, Section 2 - Flight Rules.

Cheers, 5mb :ok:

[bookworm]

Frax

The terms you describe can be used to describe airspace of any class. FIRs and UIRs are, in effect, administrative divisions of airspace, and can have any class, A to G, within them. CTAs and UTAs refer to blocks of controlled (class A to E) airspace. Some are made up of sectors of different classes.

The classification scheme will guide you as to the services provided to you and your obligations as a pilot. All airspace should have a class letter attached. The only significant difference between ICAO and US classification details I can think of is that ICAO class C and D airspace requires a clearance for VFR flights. Otherwise the services and obligations are as you would expect from the airspace class. 5milesbaby has given an excellent summary.