Airspace Structures & Restrictions

A Flight Restriction Zone (FRZ) is a permanent airspace restriction around a protected aerodrome, heliport or spaceport. You must not fly a drone or model aircraft inside an FRZ unless permission has been granted by the relevant air traffic control unit or, where air traffic control is not operational, by the aerodrome, heliport or spaceport operator.

For aerodromes, the FRZ is built from the aerodrome traffic zone and, where applicable, runway protection zones. Runway protection zones are rectangular areas extending from runway thresholds. The exact geometry for each protected aerodrome is published in the UK AIP, section ENR 5.1, and may not look identical at every site.

For heliports and spaceports, the protected area depends on the published FRZ for that site. A spaceport FRZ may differ from a conventional aerodrome FRZ. The exact boundary, vertical limit and permission contact must be checked against the published source for that location.

Unlicensed or unprotected aerodromes may not have an FRZ. That does not mean the area is risk-free. The drone operation must still comply with the normal drone rules and must not endanger aircraft using the aerodrome, circuit, approach or departure paths.

Prohibited Areas and Restricted Areas are published airspace restrictions. They are used where aviation, safety, security or public interest requirements mean that aircraft entry must be prohibited or controlled.

A Prohibited Area means flight is prohibited within the published lateral and vertical limits unless the published entry conditions allow it. For a drone operator, the answer is no: do not enter unless the published restriction itself allows the operation or the controlling authority grants permission.

A Restricted Area means flight is restricted within the published lateral and vertical limits. Entry is controlled by the conditions published for that area. If the restriction applies to unmanned aircraft, or to aircraft generally, a drone operation must comply with those conditions or obtain the required permission before entering.

These areas are published in the UK AIP, section ENR 5.1, and may also appear in current digital airspace restriction datasets and drone planning tools. The published entry condition, vertical limit and controlling authority are part of the restriction and must be checked for the actual area being considered.

A Restricted Area (Temporary), often written as RA(T), is a temporary airspace restriction. It creates a restricted area for a defined place, period and vertical limit. RA(T)s are used for events, air displays, emergency incidents, royal or state activity, security operations, aerial work and other temporary requirements.

An RA(T) is normally published by NOTAM, AIP Supplement, or both. It can also be established at short notice where the situation requires it. The published notice defines the area, height, dates, times, affected aircraft and any permission route.

A drone must not enter an active RA(T) unless the published restriction allows the operation or the controlling authority grants the required permission. The Open Category, an Operational Authorisation, or permission from a landowner does not override an active RA(T).

A Danger Area is airspace where activities dangerous to flight may take place. This can include live firing, weapons activity, explosives, demolition, high-energy activity, military training, unmanned aircraft trials or other hazardous operations.

A Temporary Danger Area (TDA) is a danger area established for a temporary period. TDAs may be used for activities such as trials, emergency operations, complex unmanned aircraft operations or other temporary hazardous activity.

A Danger Area is not the same as a Prohibited Area or Restricted Area. The legal effect and entry requirements depend on the published details for that specific area. Some Danger Areas have byelaws or restrictions that prohibit entry during activity. Others use a Danger Area Crossing Service, Danger Area Activity Information Service, scheduled activity times, NOTAMs, or a controlling authority procedure.

A drone operation must not enter an active Danger Area or TDA unless entry is allowed by the published arrangements for that area and the pilot or operator has complied with any required crossing, clearance, information or coordination procedure.

A Temporary Reserved Area (TRA) is airspace reserved for a specific activity or user during a defined period. It allows an activity to be protected or managed while still allowing other aircraft to enter where the published arrangements permit it.

A TRA is activated by the published schedule, NOTAM, AIP Supplement or other published airspace management arrangement. The published entry conditions define who may use the airspace, when it is active, what vertical and lateral limits apply, and which authority manages access.

A drone operation must not enter an active TRA unless it is the authorised activity, is included within the published arrangements, or has obtained the required clearance or coordination from the controlling authority.

A Temporary Segregated Area (TSA) is airspace segregated for a specified activity during a defined period. It is used where the activity needs separation from other airspace users.

A TSA is activated by the published schedule, NOTAM, AIP Supplement or other published airspace management arrangement. The published details define the area, height, active time, activity and controlling authority.

A drone operation must not enter an active TSA unless the operation is part of the authorised activity or the published arrangements specifically permit entry. If the TSA has been created for another user’s operation, general drone flying is not permitted inside it while active.

A Military Aerodrome Traffic Zone (MATZ) is established around many military aerodromes to protect military aircraft during approach, departure and circuit activity.

A MATZ is not controlled airspace for civil users by itself. For drone operations, the presence of a MATZ does not automatically prohibit flight. However, the same location may also contain an FRZ, Aerodrome Traffic Zone, Restricted Area, Danger Area, Prohibited Area, temporary restriction, NOTAM restriction or other airspace restriction. Those restrictions must be followed if they apply.

A standard MATZ is commonly shown as a 5 NM radius zone from the surface to 3,000 ft above aerodrome level, with approach stubs from 1,000 ft to 3,000 ft above aerodrome level. Local details vary and must be checked for the specific aerodrome.

Civil pilots can request a MATZ penetration service from the military unit. For drone operations, coordination with the relevant military unit or published contact is the appropriate route where the operation is close enough to affect military aerodrome traffic.

A Transponder Mandatory Zone (TMZ) is airspace where aircraft must carry and operate a serviceable transponder that meets the published requirement for that TMZ, unless an approved alternative arrangement applies.

A TMZ can exist in controlled or uncontrolled airspace. It does not necessarily change the airspace class, but it adds a mandatory equipment or compliance requirement for aircraft entering that volume of airspace.

Most small drones cannot comply with a conventional Mode S transponder requirement. If the drone operation cannot meet the published TMZ requirement, it must not enter the TMZ unless the published procedure allows an alternative arrangement or the responsible authority has granted permission or coordination for that operation.

TMZ details are published in the UK AIP and relevant aeronautical charting. The CAA and NATS have also identified ongoing work to centralise RMZ and TMZ information in the AIP structure, so current published data must be checked for the specific location.

A Radio Mandatory Zone (RMZ) is airspace where aircraft must comply with the published radio communication requirements before entering and while operating within the zone.

An RMZ can exist in controlled or uncontrolled airspace. It does not necessarily change the airspace class, but it adds a communication requirement for aircraft entering that volume of airspace.

A drone operation that cannot meet the published radio requirement must not enter the RMZ unless the published procedure allows an alternative arrangement or the responsible authority has granted permission or coordination for that operation.

RMZ details are published in the UK AIP and relevant aeronautical charting. The active hours, frequency, contact procedure and applicable vertical limits must be checked for the specific RMZ.

Military Low Flying Areas are areas used by military aircraft for low-level training. Military aircraft can operate at low level, at speed, by day or night, and may not be visible or audible until very close to the operating location.

A Military Low Flying Area is not a drone airspace restriction by itself. It does not automatically prohibit drone flight and it does not replace the Open Category, Specific Category, Operational Authorisation, FRZ, Restricted Area, Danger Area, NOTAM or other applicable requirements.

The safety issue is collision risk. A drone flight in an area used by low-flying military aircraft must be planned so that the remote pilot can maintain effective observation of the airspace and take action to avoid crewed aircraft. Where the operation is beyond the remote pilot’s ability to detect and avoid low-flying aircraft safely, it should not be flown under that operating method.

The MOD provides contact routes for low-flying information and enquiries. For low-level advisory information, GOV.UK lists the low level advisory service on 0800 515544. This does not grant aviation permission, but it can support deconfliction and situational awareness.