Airspace

4.1 Introduction

The airspace is divided into different classes and areas. 
The different airspaces are important to know because different services are provided within them. 
Please note that the airspace differs a lot in the European countries and you have to refer to your local vACC for more specific information. Here is however the general concept.


4.2 Types and classes of airspace [S+]

There are four types of Airspace; controlled, uncontrolled, special use and other. 
The type of airspace is dictated by the complexity and density of aircraft movements, the nature of the operations conducted, and the level of safety required.

In the uncontrolled airspace separation to other aircraft is solely the responsibility of the pilot. It is a matter of “see and be seen”. Pilots keep a good look out for other traffic and may use the radio to send blind transmissions. With “blind” transmission we mean that no answer is expected.
 
There are seven different types of airspace classes, named A to G. 
Class A-E is controlled airspace and here air traffic control service is provided. 
Class F and G are uncontrolled airspace and only flight information service (FIS) is provided.
The differences between the airspace classes are described in the next section. 

Nations and/or states may not introduce all classes of airspace, but will select those appropriate to their needs. 
In the Sweden, for example, only class C, E and G is used. In Germany class A and B is not used and so on. Refer to local manuals for the area in which you will provide ATC for more information regarding airspaces in use.
 
For the new students the important thing to remember about airspace classes is the fact that they are divided in controlled and uncontrolled airspace. When flying in controlled airspace a clearance is required, with expection of Class E which even if controlled does not require a clearance. For a controller to be able to issue a clearance, it is required that the pilot has submitted a flight-plan, and maintains two-way communication with a controller. It’s allowed to send a flight-plan via radio for VFR-flights, even though it is very seldom used on-line. 

 

 

4.2.1 Eurocontrol harmonize the upper airspace [C+]

EUROCONTROL recently harmonised the Airspace Classifications above FL 195 in “Operational Improvement 1A” and it is now Class C airspace in most member states. The upper limit in most of these countries have also been harmonised to FL 660. In addition, harmonised access rules for VFR flights in this airspace have been agreed.

This represents a significant contribution towards facilitating the Single European Sky, improving safety through reducing confusion as to airspace classification rules for those airspace users flying across Europe, and has the potential for improving Air Traffic Management efficiency through producing transparency of international airspace boundaries.

For more information about the division of airspace in different countries, please see figure F4.1 at the end of this chapter. 


4.2.2 Difference in real life and on-line [S]

Procedures on-line for different kind of airspaces might differ from those in force in real life.

Some FIR:s have a policy that all pilots shall contact the active controller before commencing a flight, even if the flight only goes through uncontrolled airspace. Please refer to local policy to gain more information regarding the policy in use where you will be controlling.

NB! All questions in Eurotest regarding airspace are referring to real life procedures, if nothing else is specified in the question.

 

4.3 Airspace classes A to G [S+]

 Controlled airspace is the airspace within which all aircraft operators are subject to certain pilot-qualifications, operating rules, and equipment-requirements.

  • For IFR operations in any class of controlled airspace, a pilot must file an IFR flight plan and receive an appropriate ATC clearance. Standard separation is provided to all aircraft operating under IFR in controlled airspace.
  • Pilots flying VFR are responsible to ensure that ATC clearance and radio communication requirements are met prior to entry into Class B, C, or D airspace.
  • Traffic advisories will be provided to all aircraft as the controller’s workload permits.
  • Safety Alerts are mandatory services which are provided to all aircraft. There are two types; Terrain/Obstruction Alerts and Aircraft Conflict Alerts.
The following paragraphs are simplified to be more easily read. 
For full description of the different airspace classes and the rules within, please refer to ICAO Annex 11 or to your local vACCs manual. 


Controlled Airspace

 

 Service/

Requirements

Class A

Class B

Class C

Class D

Class E


I

F

R

Separation between

All

All

IFR/IFR
IFR/VFR

IFR/IFR

IFR/IFR

Max. Speed

--

--

**

250 KIAS
below
FL100

250 KIAS
below
FL100

Radio required

Yes

Yes

Yes

Yes

Yes

Clearance required

Yes

Yes

Yes

Yes

Yes

 

 

 


V

F

R

Separation between

 

x

NO VFR ALLOWED

All

VFR/IFR

None

None

VMC minimums

 

See VFR section X.X.X

Max. Speed

--

250 KIAS
below
FL100

250 KIAS

250 KIAS

Radio required

Yes

Yes

Yes

No

Clearance required

Yes

Yes

Yes

No

** Some countries have max speed 250 KIAS below FL100, some don’t.

Uncontrolled Airspace

 

 Service/

Requirements

Class F

Class G


I

F

R

Separation between

IFR/IFR as far as possible

None

Max. Speed

250 KIAS

250 KIAS

Radio required

Yes

Yes

Clearance required

No

No


V

F

R

Separation between

None

None

VMC minimums

See VFR section X.X.X

Max. Speed

250 KIAS

250 KIAS

Radio required

No

No

Clearance required

No

No

Simplified - SVFR-flights (where allowed) are treated as IFR in regards of separation.


4.3.1 Class A (controlled) [C]

Class A airspace is generally the airspace from FL195 up to and including FL 660. 
Unless otherwise authorized, all pilots must operate their aircraft under IFR. 
Class A Airspace is not specifically charted.


4.3.2 Class B (controlled) [C]

Class B airspace is generally the airspace from the surface to FL100, surrounding the busy airports in terms of airport operations or passenger emplacements. 
The configuration of each Class B airspace area is individually tailored and consists of a surface area, and two or more layers (some Class B airspace areas resembles upside-down wedding cakes), and is designed to contain all published instrument procedures once an aircraft enters the airspace.


4.3.3 Class C (controlled) [C]


Separation between IFR flights and between IFR and VFR is provided in class C airspace. 
Separation between VFR and VFR is not provided, but traffic information is provided by ATC and can also be requested by VFR traffic when needed. 

 

4.3.4 Class D (controlled) [C]


Class D airspace provides standard separation between IFR/IFR, and provides traffic information about VFR. 
Separation between VFR and VFR is not provided, but traffic information is provided by ATC and can also be requested.

 

4.3.5 Class E (controlled) [C]

Class E airspace provides standard separation between IFR/IFR, and provides traffic information about VFR. 
Separation between VFR and VFR is not provided and traffic information is provided as far as practical. 

 

4.3.6 Class F (uncontrolled) [C]

Class F airspace provides Advisory Service between IFR/IFR separation as far as practical.

Flight information service (FIS) is provided between VFR/IFR and VFR/VFR,.

 

4.3.7 Class G (uncontrolled) [C]

Class G airspace provides FIS to all flights.

 

4.4 Types of airspace – Controlled airspace [S]

The different airspace classes determines what kind of service and requirements that ATC and aircraft has to give and meet. 
The airspace is also divided into different types of airspace. 
We start with the controlled airspace, which can be divided into three different types. 
Please note that there are big differences between countries regarding the airspace structure!

 

4.4.1 Control Zone (CTR) [S+]

Around all controlled aerodromes (airports) there are control zones. 
A control zone is established to protect the aerodrome traffic. 
The coverage of a CTR is usually about 10 to15 kilometres horizontally from the airport and vertically from the ground up to 1000-5000ft above ground level (AGL). 
This can however differ quite substantially from airport to airport and you have to take a closer look at the AIP over the airport you are manning to make sure you know the boundaries of the airspace. 

 

4.4.2 Terminal Area (TMA) [S+]

Above and/or laterally to the controlzone is a TMA. 
A TMA is usually of class C airspace. 
The lower limit of the TMA is normally around 1000-5000ft feet AGL and the upper limit is normally FL95. It is common that the lower limit of the TMA is increased in steps from the airport. 
The construction of the TMA differs a lot from country to country, so you have to refer to your local vACC for more information. 

 

4.4.3 Control Area (CTA) [S+]

The Control Area covers a bigger area in the air and is situated above and around TMA:s. 

 

4.5 Types of airspace – Uncontrolled airspace [C+]

That the uncontrolled airspace is ‘uncontrolled’ means that no air traffic control is provided, only flight information service (FIS). Pilots are not required to request clearance to fly in uncontrolled airspace. It is the pilot's responsibility to keep separated to other traffic. 
Flights in uncontrolled airspace can request information about other traffic from ATC – “traffic information”. 
Please note that rules regarding how to handle traffic in uncontrolled airspace differ from vACC to vACC. And TIZ and TIA are non-existent in many countries.

 

4.5.1 Traffic Information Zone (TIZ) [C+]

A TIZ can be found closest to the ground around some airports. Information service is provided here and not control.

This also means that special phraseology is used when communicating with pilots. 
Emergency assistance is also provided. 


4.5.2 Traffic Information Area (TIA) [C+]

TIA is situated above a TIZ and functions in the same way; no control of traffic, just traffic information.


4.6 Airways and Routes [C]

There are two fixed Airway systems established for Air Navigation. 
These are the Low Altitude Airways (Lower) and the High Altitude Airways (Upper). 
In addition, we are also talking about VOR and LF/MF routes. 
The following is a brief description of the three.

 

4.6.1 Low altitude Airways [C]

Low Altitude Airways is a system consisting of designated airways, ranging from FL055 (in some cases higher) up to FL195-285*. These airways are depicted on En Route Low Altitude Charts, e.g. "G1" or "Golf One".

* The lower and upper level varies from country to country. 

 

4.6.2 High altitude Airways [C]

High Altitude Airways is a system consisting of designated airways, ranging from FL195-285* and upwards. These airways are designated with a preceding "U" in front of the standard route number, e.g. Route "G1" for Upper airways would be "UG1" or "Upper Golf One". These airways are depicted on En Route High Altitude Charts.

* The level varies from country to country. 

 

4.6.3 VOR and LF/MF Routes [C+]

VOR and LF/MF Routes consists of airways designated from 1,500 feet above the surface (in some cases higher) up to, but not including FL195. These airways are depicted on En Route Low Altitude Charts.

VOR Routes are based solely on VOR airways, and are identified by the airway number.
Except to effect transitions within or between route structures, the altitude limits of airways should not be exceeded.

LF/MF airways are based on LF/MF navigation aids, and are depicted brown on charts. You will find these airways mostly over the ocean. They are colored Green and Red for East/West routes, and Amber and Blue for North/South routes.

 

4.6.4 Route Directions [S+]

Some routes are one-way-only, meaning that traffic can only go in one direction on that route. This is to facilitate separation. On some routes traffic is allowed both ways. 

In some countries the routes are numbered according to a special system– i.e. odd routes going from south to north and even from north to south. Exceptions are quite common however and some countries don’t have that kind of system at all. 

 

4.7 RVSM [C]

A long time ago, when instruments were not as reliable as they are now, it was decided to apply a minimum vertical separation of 2000 ft above the FL 290, keeping a 1000 ft spacing below this level. So until now, we had the CVSM (Conventional Vertical Separation Minimum) as follows :

  • 1000 ft spacing below FL 290
  • 2000 ft spacing above FL 290

From January 24th, 2002, this rule was changed with the implementation of RVSM (Reduced Vertical Separation Minimum). This was due to the quality of flight instruments now installed onboard aircraft. They are more reliable and more accurate that those of the previous decades. 
Considering this fact, in addition to the necessity of increasing the control capacity in upper airspace sectors, it was decided to reduce the spacing from 2000 ft to:

  • 1000 ft between FL 290 and FL 410.

4.8 MNPS/RVSM Approval [C+]

MNPS stands for Minimum Navigation Performance Specifications, representing those requested for an aircraft to be RVSM approved. These MNPS are for aircraft able to fly between FL 290 and 410. According to these rules the aircraft can fly into RVSM airspace if is equipped with:

  • Redundancy altitude device, with high standards of accuracy and reliability.
  • New generation TCAS. (TCAS II Version 7 and later on).
  • Autopilot with advanced altitude hold features. (no oscillations over 75ft at ALT HOLD mode)

All aircraft which came out from factories these last 5 years match with these specifications. Most of other planes have been modified to be RVSM approved, thus bringing to about 95% the rate of aircraft concerned by RVSM which are effectively RVSM approved.

Some old generation aircraft (DC-8, DC-3, B707...) haven’t been updated because their operators found it to be too expensive. 
Also, some military aircraft, and particularly combat aircraft, are not RVSM approved (technical and operational imperatives are different from commercial aircraft).

 

4.8.1 RVSM/MNPS Policy of VATSIM-EUROPE Division [C+]

The only MNPS applicable in our virtual world are the altimeter and the autopilot to be fully operational and therefore VAT-EUD consider all aircraft capable of flying in RVSM airspace. 
If the pilot wants to fly the "old fashion" way, (if handling a DC-8 for instance), he has to indicate this particular information in the flight plan remark: NON-RVSM. 
Some pilots are using “failure features” in FS and hence the altimeter or autopilot may malfunction. If this happens, the pilot is to inform ATC that he can’t fly according to RVSM-rules. 

 

Figure F4.1 – division of airspace in Europe [Ref]