What is airspace?

In simple terms, the sky over the UK comprises of airspace that is categorised as controlled or uncontrolled. Most gliding takes place in uncontrolled airspace.

All airspace, including uncontrolled airspace, is subject to temporary restrictions and changes – always refer to NOTAMs before flight. The following detail is supplied to assist pilots. In all cases, the applicable legislation takes precedence.

Introduction to airspace and airspace classifications

There is a helpful ‘Introduction to airspace’ here, which includes descriptions of airspace classifications.

UK airspace is classified from A to G within which rules of the air and differing limitations are applicable in each classification.  There are pro’s and con’s of airspace classifications:

A – Not available to gliders other than under the terms of a specific Letter of Agreement (LOA).

B – Not currently used in the UK

C – Can be used by gliders, but a clearance is required and you must comply with ATC instructions. You probably won’t be allowed in without a transponder, and prior notification of your intentions to ATC will help. Be prepared for additional workload dealing with ATC. All TRA(G) (aka Wave Boxes) above FL195 are in Class C.

  • Pros: Accessible in principle.
  • Cons: Flights need to be planned, close coordination with ATC required.

D – The most common Controlled Airspace at low level. Gliders can enter with a clearance, but unless you’re in an area that’s used to dealing with gliders you may have difficulty. Managing multiple VFR aircraft mixing with commercial traffic is hard work for controllers, particularly when your track isn’t precisely predicable. Good radio discipline is essential, and a transponder will definitely help. LOA’s and/or protocols in Class D can create ‘standard’ clearances which can result in easier access to Class D for both pilot and controller.

  • Pros: Accessible in principle
  • Cons: ATSU’s may be reluctant to grant a clearance to gliders, and the workload associated with ATC liaison may impact your soaring performance.

E – Effectively uncontrolled airspace (Class G-like) for VFR gliders, controlled airspace for IFR gliders. So no communication with ATC required if VFR. Gliders are unlikely to be able to obtain an IFR clearance.

  • Pros: Fully accessible for VFR flights
  • Cons: Not accessible for IFR flights – close to cloud even though flying visually above 3000′ amsl.

Class E often comes with an additional TMZ requirement, known as Class E+

TMZ – Transponder Mandatory Zone. If Transponder equipped, aircraft can enter without any need to contact ATC. If not transponder equipped, normally entry is still possible with prior permission from ATC if you have a FRTOL. The phraseology will involve “approving” the entry, ATC will not give a clearance because you can’t have a clearance for flight in Class G or for VFR flight in Class E.

  • Pros: Fully accessible if you are transponder equipped
  • Cons: Conversation with ATC required if you are not transponder equipped.

F – Not currently used in the UK.

G – Free for all, see and avoid (ideally supported with EC)

  • Pros – just do your thing.
  • Cons – so is everyone else.

Within the airspace classifications, other categories of airspace exist, for example:

Aerobatic Competitions and Boxes

The aerobatic community fly aerobatics within defined aerobatic boxes. These are often promulgated in NOTAMs. Please be aware that whilst aerobatic pilots have to compy with the rules of the air and lookout as much as other class G users, the nature of competition aerobatics is that the majority of the pilots time will be focussed on achieving specific attitudes and the desired aircraft trajectory. In addition to the important safety aspects, there is also a need to give these fellow air sport pilots the space they require to enjoy their sport.


The status of an Air Traffic Zones (ATZ) can confuse pilots. Some pilots get caught out by not being prepared and thereby not complying with their legal obligation before entering an ATZ. Pilots are reminded that illegal entry into an ATZ can result in a Mandatory Occurrence Report and infringement action by the CAA.

During an ATZ’s notified operating hours:

  • a pilot may only enter an ATZ served by Air Traffic Control (ATC) and operate within the ATZ when permission has been granted by ATC. Note – permission must be sought before entering the ATZ.
  • a pilot may only enter an ATZ served by a Flight Information Service or Air/Ground service and operate within the ATZ when two-way contact has been established. Note – two-way contact must be established before entering the ATZ.

More details are available here.

Danger Areas and Temporary Danger Areas

A danger area (DA) can be permanent or temporary in nature. An example of a permanent DA is D129 at Weston on the Green. An example use of a temporary danger area (TDA) is where a TDA is established for Beyond Visual Line Of Sight (BVLOS) drone trials. DA’s and TDA’s often have a Danger Area Crossing Service (DACS) and/or a Danger Area Activity Information Service (DAAIS). Pilots are reminded that unauthorised entry into a danger area can result in a Mandatory Occurrence Report and infringement action by the CAA. The CAA DA and TDA policy is available here.

Instrument Procedural Traffic

A number of airfields in the UK have instrument traffic procedures which are detailed in the UK AIP but not shown on 1/2 mil charts. In some cases the instrument approaches are indicated by a feather on the ½ mil chart (for example Cambridge, Gloucester, Exeter, Inverness, Cranfield, Londonderry, Oxford). These feathers can be indicated on most GPS moving map software.

Invariably, instrument traffic operating in Class G is not looking out as effectively as most would expect. Glider pilots should aim to avoid the airfield overhead and the approach areas.

Here is an example of the instrument approach procedure that is not marked on the 1/2 mil charts used by most pilots:

When operating close to these airfields, pilots should listen out on the ATC frequency. Where there is a need to operate overhead the airfield, or when vertically close to and when horizontally within say an approximate 20 degree arc either side of the instrument approach ‘slope’, it can be very helpful if the glider pilot makes contact with ATC prefixing the call with ‘glider’, stating their location (eg 5nm NE of the airfield at 2000’) and stating their intentions (eg to climb, to glide to xxxxx, etc). Please don’t forget that last minute calls can result in pilot overload as the pressure comes on. Most air traffic controllers have little appreciation of pilot workload but will help where they can. As ever, aviate, navigate and communicate in that order.

There is helpful guidance in this Cambridge GC youtube briefing.

Letters of Agreement (LOA’s)

Letters of Agreement (LOA’s) between the BGA and Air Traffic Service Units (ATSUs) can simplify glider access to controlled airspace – the TRA(G)‘s are an example of this. They need to be specifically negotiated and periodically reviewed, and often apply only to gliders operating from named BGA clubs.


A Military Air Traffic Zone is a 5nm radius x 3000′ high defined volume of airspace around a military ATZ. A MATZ has no legally recognised status for civil pilots and no prior permission is required to enter it. However, for safety and good airmanship reasons, prior to entering a potentially busy MATZ, pilots are encouraged to establish radio communications with the controlling authority. This is particularly important when flying close to active military fast jet and training airfields – those aircraft need space to manouevre. Military airfields such as Barkston Heath, Coningsby, Cranwell, Lossiemouth, Middle Wallop and Shawbury are examples of active busy military airfields.


All pilots are expected to check NOTAMs (Notices to Aviation) before flight. Learning how to simply access NOTAMs forms a part of glider pilot training. Any pilot who is unsure about how to check NOTAMs is advised to discuss the matter with his or her CFI or with another experienced pilot. The CAA’s tutorial on accessing AIS NOTAM data is here. There are several excellent apps available that help pilots easily access and interpret AIS NOTAM data, including Skydemon.

Parachute Drop Zones

Pilots are reminded that unauthorised entry into a DZ resulting in a hazard can result in a Mandatory Occurrence Report and infringement action by the CAA. You can find parachute drop zone frequencies and other detail here.


A Restricted Area (Temporary) also known as a RA(T), is a temporary airspace structure established under article 239 of the Air Navigation Order (ANO) 2016 to ensure the safety of participants or attendees during specific events/activities or for reasons of National Defence or any other reason affecting the public interest.
A RA(T) will always be designed to restrict aircraft using the minimum amount of airspace to achieve this aim. Whilst most are areas of specified radius, some RA(T)s can be more complex in shape. Some examples of events/activities where a RA(T) may be established include Airshows, Air Racing, Flypasts, Festivals, and Specific Helicopter Flights.

As a RA(T) is specific to individual locations and event, an airshow with slower participants displaying at lower altitudes will have a smaller RA(T) than one which has, for example, a fast jet display carrying out high energy manoeuvres. This affords the aircraft engaged in display manoeuvres protection from unknown traffic but does not restrict transit traffic through the area disproportionately. Due to manoeuvres associated with displaying a large formation team (such as the Red Arrows), shorter, individual displays, although part of the bigger event, require a larger volume of restricted airspace. In 2022, 115 RA(T)s were established under article 239 of the ANO 2016.
A RA(T) can be promulgated in three combinations:
1. NOTAM and Aeronautical Information Circular (AIC),
2. NOTAM and Briefing Sheet, or

Pilots are reminded that unauthorised entry into a RA(T) will result in a Mandatory Occurrence Report and infringement action by the CAA.

TMZ (Transponder Mandatory Zone) and RMZ (Radio Mandatory Zone)

There are specific requirements for accessing TMZ’s and RMZs. Pilots are reminded that unauthorised entry into a TMZ or RMZ can result in a Mandatory Occurrence Report and infringement action by the CAA.  You can read the CAA’s policy here.

Non-transponder areas above FL100

In 2012 the BGA negotiated a number of non-transponder areas above FL100. These are detailed as exceptions in the UK AIP under ENR 1.1 and 5.2. The CAA has advised (21st January 2022) that no exemption or permission is required for non-transponder high altitude glider flights in specified areas, based on the current rules, notified airspace and the exception listed in the AIP. Please note that transponder equipage is required above FL100 when flying outside the notified non-transponder areas for gliders.

You can view the areas in the AIS AIP at ENR 6-63 (non-transponder areas above FL100), and 6-64, 6-65 and 6-66 (temporary reserved areas FL195-FL245).

There is an extract showing the non-transponder areas above FL100 here.

The TRA(G) areas are detailed in a LOA here.

Here is the background detail justifying not issuing an exemption. Article 77 and and Schedule 5,  17.— Transponder requires carriage of such SSR equipment, in particular where there are (ii) any notified airspace requirements. The notified airspace requirements are set out in UK AIP GEN 1.5 para 5.3, in the table under Of note is the requirement (d) that all aircraft operating under VFR within United Kingdom airspace at and above FL 100 require Mode S Elementary Surveillance. However, para 5.3.4 sets out the exceptions which notes that the requirements at sub-paragraphs (c) to (e) shall not apply to gliders, including self-sustaining gliders and self-propelled hang gliders, and self-launching motor gliders where operating above FL 195 inside airspace notified as TRA(G), where operating below FL 195 inside notified Non-SSR Transponder Glider Areas.

There is a comment in that the exception at paragraph (a)(ii) applies in accordance with any specific permission issued by the CAA and published on its website. CAA lawyers advice (21 Jan 22) is that this is unnecessary, as gliders are not caught by article 77, as they are not notified as such, so do not, in those circumstances, need to carry SSR equipment, and therefore do not need an exemption or a permission, as it is allowed for by those articles, by their terms. In light of this legal view and guidance, the CAA will no longer be issuing further exemptions. The note in the AIP will be amended to remove the current text in In addition, new text will be added that provides guidance along the lines of the exemption material text (e.g. the pilot in command to obtain the permission of the appropriate air traffic control unit to fly within airspace notified as Class C or D airspace and complies with any instructions given by the air traffic control unit)

The NSGA Zone 1 NOTAM text in will remain.

Rules of the Air

Rules of the Air links are available on our Laws and Rules webpage.