Editing Airspace class (section)

== ICAO definitions ==
On March 12, 1990, ICAO adopted the current airspace classification scheme.<ref>ICAO's airspace classification scheme is defined in ICAO Annex 11: Air Traffic Services, Chapter 2, Section 2.6, available at {{cite web|url=http://www.icao.int/safety/ism/ICAO%20Annexes/Forms/AllItems.aspx |title=ICAO Annexes - All Documents |access-date=2014-04-05 |url-status=dead |archive-url=https://web.archive.org/web/20140407130450/http://www.icao.int/safety/ism/ICAO%20Annexes/Forms/AllItems.aspx |archive-date=2014-04-07 }}</ref> The classes are fundamentally defined in terms of [[flight rules]] and interactions between [[aircraft]] and [[air traffic control]] (ATC). Generally speaking, the ICAO airspaces allocate the responsibility for avoiding other aircraft, namely either to ATC (if separation is provided) or to the aircraft commander (if not).

These airspace classifications were put into use in the US in September, 1993.

Some key concepts are:
*[[Separation (aeronautics)|Separation]]: Maintaining a specific minimum distance between an aircraft and another aircraft or terrain to avoid collisions, normally by requiring aircraft to fly at set levels or level bands, on set routes or in certain directions, or by controlling an aircraft's speed.
*Clearance: Permission given by ATC for an aircraft to proceed under certain conditions contained within the clearance.
*Traffic information: Information given by ATC on the position and, if known, intentions of other aircraft likely to pose a hazard to flight.
* Flight rules: Aircraft can operate under [[visual flight rules]] (VFR) or [[instrument flight rules]] (IFR). There is also an intermediate form, [[special visual flight rules]] (SVFR).

===ICAO adopted classifications===

''Note: These are the ICAO definitions. Country-specific adaptations (such as "two-way communications" instead of "clearance" for Class C in the US) are discussed in the sections below.'' <!-- please do not place them here-->

*'''Class A''': All operations must be conducted under IFR. All aircraft are subject to ATC clearance. All flights are separated from each other by ATC.
*'''Class B''': Operations may be conducted under IFR, SVFR, or VFR. All aircraft are subject to ATC clearance. All flights are separated from each other by ATC.
*'''Class C''': Operations may be conducted under IFR, SVFR, or VFR. All aircraft are subject to ATC clearance (country-specific variations notwithstanding). Aircraft operating under IFR and SVFR are separated from each other and from flights operating under VFR, but VFR flights are not separated from each other. Flights operating under VFR are given traffic information in respect of other VFR flights.
*'''Class D''': Operations may be conducted under IFR, SVFR, or VFR. All flights are subject to ATC clearance (country-specific variations notwithstanding). Aircraft operating under IFR and SVFR are separated from each other, and are given traffic information in respect of VFR flights. Flights operating under VFR are given traffic information in respect of all other flights.
*'''Class E''': Operations may be conducted under IFR, SVFR, or VFR. Aircraft operating under IFR and SVFR are separated from each other, and are subject to ATC clearance. Flights under VFR are not subject to ATC clearance. As far as is practical, traffic information is given to all flights in respect of VFR flights.
*'''Class F''': Operations may be conducted under IFR or VFR. ATC separation will be provided, so far as practical, to aircraft operating under IFR. Traffic Information may be given as far as is practical in respect of other flights.
*'''Class G''': Operations may be conducted under IFR or VFR. ATC has no authority but VFR minimums are to be known by pilots. Traffic Information may be given as far as is practical in respect of other flights.
Special Airspace: these may limit pilot operation in certain areas. These consist of Prohibited areas, Restricted areas, Warning Areas, MOAs (military operation areas), Alert areas and Controlled firing areas (CFAs), all of which can be found on the flight charts.

Classes A–E are referred to as [[controlled airspace]]. Classes F and G are [[uncontrolled airspace]].

The table below provides an overview of the above classes, and the specifications for each.

{| class="wikitable"
|-
! Class !! [[Controlled airspace|Controlled]] !! [[Instrument flight rules|IFR]] !! [[Special visual flight rules|SVFR]] !! [[Visual flight rules|VFR]] !! ATC clearance !! Separation !! Traffic information
|-
| A || {{yes|Controlled}} || {{yes}} || {{no}} || {{no}} || Required || Provided for all flights || N/A
|-
| B || {{yes|Controlled}} || {{yes}} || {{yes}} || {{yes}} || Required || Provided for all flights || N/A
|-
| C || {{yes|Controlled}} || {{yes}} || {{yes}} || {{yes}} || Required || Provided for all IFR/SVFR to  IFR/SVFR/VFR|| Provided for all VFR
|-
| D || {{yes|Controlled}} || {{yes}} || {{yes}} || {{yes}} || Required || Provided for IFR/SVFR to other IFR/SVFR || Provided for all IFR and VFR
|-
| E || {{yes|Controlled}} || {{yes}} || {{yes}} || {{yes}} || Required for IFR and SVFR || Provided for IFR/SVFR to other IFR/SVFR || Provided for all IFR and VFR flights where possible
|-
| F || {{no|Uncontrolled}} || {{yes}} || {{no}} || {{yes}} || Advisory only || Provided for IFR/SVFR to other IFR/SVFR where possible || Provided where possible if requested
|-
| G || {{no|Uncontrolled}} || {{yes}} || {{no}} || {{yes}} || Not provided || Not provided || Provided where possible if requested
|}