Uncontrolled airspace

{{short description|Airspace without an air traffic control service}}

In aviation, uncontrolled airspace is airspace in which an Air Traffic Control (ATC) service is not deemed necessary or cannot be provided for practical reasons. It is the opposite of controlled airspace. It is that portion of the airspace that has not been designated as Control Area, Control Zone, Terminal Control Area or Transition Area.{{cite book |last1=Kumar |first1=Bharat |last2=DeRemer |first2=Dale |last3=Marshall |first3=Douglas M. |title=An Illustrated Dictionary of Aviation |date=2004|publisher=McGraw-Hill |location=New York |isbn=978-0-07-139606-6 |page=671 |ref=Kumar}}

According to the airspace classes set by the International Civil Aviation Organization (ICAO), the uncontrolled classes of airspace are class F and G.{{Cite web |title=Classification of Airspace {{!}} SKYbrary Aviation Safety |url=https://www.skybrary.aero/articles/classification-airspace |access-date=2023-05-24 |website=www.skybrary.aero}}

Class F

Class F (uncontrolled) is rarely encountered in ICAO member-states' airspace systems. In the UK, it was formerly a hybrid between class E (controlled) and G (uncontrolled) as Advisory Routes (ADRs).{{cite web |author1=FLYER |title=CAA announces replacement of Class F Airspace |url=https://www.flyer.co.uk/caa-announces-replacement-of-class-f-airspace/ |publisher=Seager Publishing |location=Melksham |date=10 September 2014}} In the UK, all airspace previously designated as class F was re-assigned to either class E or G on 13 November 2014.{{cite web |author1=Safety and Airspace Regulation Group |title=Replacement of class F airspace in UK FIRs |url=https://www.caa.co.uk/WorkArea/DownloadAsset.aspx?id=4294972711 |publisher=Civil Aviation Authority |access-date=2 May 2021 |location=London |date=30 July 2014}}{{cite web |author1=Civil Aviation Authority |title=CAA announces replacement of Class F Airspace |url=https://www.atc-network.com/atc-news/united-kingdom-civil-aviation-authority/caa-announces-replacement-of-class-f-airspace |publisher=ATC Network |location=London |date=11 September 2014}}

Class G

Individual countries designate different portions of airspace as class G, e.g. in the UK, airspace above FL660 (Flight Level 660 or 66,000 feet) is uncontrolled and belonging to class G,{{cite book |last1=Smith |first1=David |title=Air Traffic Control Handbook |publisher=Crécy |location=Manchester |isbn=978-08597-91830 |page=37 |date=2015 |edition=10th |ref=Smith}} while in the US, any airspace above FL600 (60,000 feet) is designated as class E and therefore controlled.{{cite web |author1=Federal Aviation Administration |title=AIM (Aeronautical Information Manual). Official Guide to Basic Flight Information and ATC Procedures |url=https://www.faa.gov/air_traffic/publications/media/aim.pdf |publisher=U.S. Department of Transportation |access-date=2 May 2021 |pages=137–138 |date=12 October 2017}} Similarly, large parts of lower airspace in the UK are uncontrolled while in the US any airspace above 700-1200 feet up to FL145 (14,500 feet), not designated as any other class of airspace (A-D) belongs to class E and is controlled.

Air traffic control

ATC does not exercise any executive authority in uncontrolled airspace, but may provide basic information services to aircraft in radio contact.{{cite web |last1=Kelly |first1=Brendan |title=The hidden secrets of UK airspace: Airspace classifications |url=https://nats.aero/blog/2017/05/hidden-secrets-uk-airspace-airspace-classifications/ |publisher=NATS |access-date=2 May 2021 |date=10 May 2017}} The aircraft commencing its flight in uncontrolled airspace, and subsequently proceeding into controlled airspace, should obtain clearance from the ATC unit in whose area the controlled part will begin.{{cite web |author1=International Civil Aviation Organization |title=Doc 4444 Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM) |date=2016 |url=https://ops.group/blog/wp-content/uploads/2017/03/ICAO-Doc4444-Pans-Atm-16thEdition-2016-OPSGROUP.pdf |website=OPS Group |access-date=2 May 2021 |ref=Doc4444 |page=52 |archive-date=6 May 2021 |archive-url=https://web.archive.org/web/20210506183748/https://ops.group/blog/wp-content/uploads/2017/03/ICAO-Doc4444-Pans-Atm-16thEdition-2016-OPSGROUP.pdf |url-status=dead }} If a flight starts in controlled airspace but its subsequent portion will be uncontrolled, its clearance should be up to the point at which the controlled portion of the flight terminates.

Flight in uncontrolled airspace will typically be under VFR. Aircraft operating under IFR should not expect separation from other traffic; however, in certain uncontrolled airspace, this might be provided on an 'as far as is practical' advisory basis. Controlled flights should not be vectored (directed) by ATC into uncontrolled airspace except for weather avoidance or in an emergency.

References

Category:Air traffic control