Policy paper

Control of development in airport public safety zones

Updated 8 October 2021

Basic policy objective

Public safety zones (PSZs) are end of runway areas. Development within PSZs is restricted so as to control the number of people on the ground at risk of death or injury should an aircraft accident occur during:

• take-off
• landing

The policy objective governing the restriction of PSZ development near civil airports is that there should be no increase in the number of people:

• living
• working
• congregating

Plus that, over time, the number should be reduced as circumstances allow.

Zone contours

The implementation of PSZ policy at civil airports is based on the level of risk to people on the ground around airports.

The extent of zone contours is based upon aircraft accident data.

The PSZ policy is based predominantly on individual risk, while extending beyond it in relation to particular types of developments for example transport infrastructure and temporary uses.

The areas of the PSZs essentially correspond to the concentration of accident location, based on relevant data.

The resultant shape of a PSZ is that of an elongated isosceles triangle. In all cases, an airport’s PSZs are based on the landing threshold for each end of the relevant runway and taper away from the runway.

An airport’s PSZs will need to be redefined if a:

• runway is extended
• landing threshold is moved

or

• there is an increase in commercial air transport movements (ATMs) on the runway

The basis of the policy of restricting new development within PSZs is constrained to a cost versus benefit analysis.

The cost versus benefit analysis is a risk appraisal principle under which individual risk is reduced to a tolerable level irrespective of cost and then further reduced only if the benefits of doing so exceed the costs. Within the PSZs there are public safety benefits from preventing any new or replacement development or change of use, which would result in an increase in the numbers of people:

• residing within the zones
• working within the zones

The economic costs of removing existing development throughout the zones would, however, outweigh the safety benefits of doing so, and the Secretary of State for Transport is therefore not proposing that course.

Risk appraisal

Although the boundaries of the PSZs correspond essentially to the location of accidents, the level of risk in some areas within the zones may be much higher. The Secretary of State, therefore, regards the area closest to the runway with a significant amount of crash data as a public safety restricted zone (PSRZ). At some airports, the PSRZ extends beyond the airport boundary and includes occupied property. In other cases, there is no occupied development within the areas concerned, or the areas concerned are contained wholly within airport boundaries.

Purchase of property by airport operators

The Secretary of State wishes to see, within an airport’s PSRZ, the emptying of all the:

• occupied residential properties
• commercial and industrial properties occupied as normal all-day workplaces

In cases:

• where any part of a residential property falls within this zone the Secretary of State will expect the operator of an airport for which PSZs have already been established to make an offer to purchase the property or at option of the owner, the part of its garden or land as falls within this contour
• of commercial or industrial property the Secretary of State expects operators to make an offer to purchase, in whole or in part that property if, or the relevant part of it, is occupied as a normal all-day workplace and falls within this contour.

If the part of the property in question is discrete or self-contained, and its loss would not materially affect the business concerned, only that part need be the subject of such an offer otherwise the airport operator should offer to purchase the entire property.

In the case of airports for which PSZs are established or redefined after the date of this circular, the Secretary of State will expect the operators to make required offers within 12 months of the notification of the PSZs and the PSRZ.

The Secretary of State will expect all such offers to be kept open indefinitely. If an owner wishes to sell a property, the airport operator should apply the Compensation Code. The Compensation Code is not a single document but a collective term used including, among others, the:

1. Principles set out in Acts of Parliament, principally the Land Compensation Act 1961.
2. Compulsory Purchase Act 1965, the Land Compensation Act 1973.
3. Planning and Compulsory Purchase Act 1991 and the Planning and Compulsory Purchase Act 2004 this is supplemented by case law, relating to compensation for compulsory acquisition.

Airport operators will be expected to demolish any buildings purchased and to clear the land.

The Secretary of State will be prepared to consider applications for compulsory purchase orders by airport operators with powers under section 59 of the Airports Act 1986, providing applications can demonstrate a compelling case in the public interest.

Establishment of PSZs

PSZs are established at all the airports that traffic more than 18,000 commercial air transport movements per year.

They comprise an outer boundary which is Public Safety Controlled Zone (PSCZ) and an inner, higher risk zone, which is the PSRZ.

The length of the PSCZ for an aerodrome with fewer than 45,000 commercial ATMs per year has been set at 1,000 metres from the landing threshold.

For an aerodrome with greater than 45,000 commercial ATMs, the PSCZ follows the same lateral plan but extends to 1,500 metres.

Regardless of the number of commercial ATMs, the PSRZ has been set at 500 metres from the landing threshold.

The width of the:

• PSRZ at the landing threshold is 75 metres either side of the runway centreline
• PSCZ at the landing threshold is 140 metres either side of the runway centreline

The standardised shape that replaces the risk-based model profile has been defined using the latest data on accidents shown to be located outside the aerodrome boundary.

Role of the local planning authorities

This policy contains guidance to local planning authorities to enable them to decide planning applications and consider road proposals affecting land within PSZs.

Local planning authorities need to carry out risk assessments in determining the use of land for sites within PSZs unless they are following either the:

or

• development permissible within PSZs guidance

The principle of constrained cost-benefit analysis underlies the specific guidance contained in that guidance.

It will normally be necessary for local authorities to consider whether the granting of an individual planning application would lead to an increase in the number of people living, working or congregating in the PSZs unless following the specific guidance.

General presumption against development within PSZs

There should be a general presumption against:

• new or replacement development within PSZs
• changes of use of existing buildings, within PSZs

In particular, this should not permit:

• new or replacement dwelling houses or non-residential development
• mobile homes
• caravan sites
• other residential buildings

Exceptions to this general presumption are set out in development permissible within PSZs guidance.

Development permissible within PSZs

Two types of exceptions to the general presumption may be permitted within those parts of PSZs outside any PSRZ.

First, it is not considered necessary to refuse permission on PSZs grounds for when it is either:

• an extension or alteration to a dwelling which is for the purpose of enlarging or improving the living accommodation for the benefit of the people living in it, such people forming a single household, or which is for the purpose of a ‘granny annex’
• an extension or alteration to a property (not being a single dwelling or other residential building) that could not reasonably be expected to increase the number of people working or congregating in or at the property beyond the current level or, if greater, the number authorised by any extant planning permission
• a change of use of a building or of land which could not reasonably be expected to increase the number of people living, working or congregating in or at the property or land beyond the current level or, if greater, the number authorised by any extant planning permission

Second, certain forms of new or replacement development which involve a low density of people living, working or congregating may be acceptable within a PSZ. Examples of these might include:

1. Long stay and employee car parking (where the minimum stay is expected to be in excess of 6 hours).
2. Open storage and certain types of warehouse development. ‘Traditional’ warehousing and storage use, in which a very small number of people are likely to be present within a sizeable site, is acceptable. But more intensive uses, such as distribution centres, sorting depots and retail warehouses, which would be likely to entail significant numbers of people being present on a site, should not be permitted. In granting consent for a warehouse, a local planning authority should seek to attach conditions that would prevent the future intensification of the use of the site and limit the number of employees present.
3. Development of a kind likely to introduce very few or no people on to a site on a regular basis. Examples might include unmanned structures, engineering operations, buildings housing plant or machinery, agricultural buildings and operations, buildings and structures in domestic curtilage incidental to the principal dwelling and buildings for storage purposes ancillary to existing industrial development.
4. A public open space, in cases where there is a reasonable expectation of low-intensity use, such as car boot sales. Attractions such as children’s playgrounds should not be established in such locations. Nor should playing fields or sports grounds be established within PSZs, as these are likely to attract significant numbers of people on a regular basis.
5. Golf courses, but not clubhouses.
6. Allotments.

The principal feature of the general policy in relation to buildings and land within any PSRZ is that people should not be expected to live or have their workplaces within such areas. Consequently, very few uses will be acceptable within this zone.

Certain forms of development which involve a very low density of people coming and going may, however, be acceptable. Examples of these might include:

1. Long stay and employee car parking (where the minimum stay is expected to be in excess of 6 hours).
2. Built development for the purpose of housing plant or machinery, and which would entail no people on-site on a regular basis. For example, this may include boiler houses, electricity switching stations or installations associated with the supply or treatment of water.
3. Golf courses, but not clubhouses.

Reference to the Department for Transport

A local planning authority may exceptionally receive applications for other forms of development on sites within PSZs for which it may consider that there is a reasonable expectation of low-density occupation and may therefore be minded to grant planning permission. The authority may wish to consult the Aviation Safety team in the Department for Transport, which may be able to advise on whether the proposed land use is broadly consistent with the PSZ policy.

Conditions

Local planning authorities should consider the use of suitably worded conditions in appropriate cases in order to limit the number of people who might be expected to be present on-site at any time. In doing so they should take into account the qualifying criteria for conditions, set out in the National Planning Policy Framework.

Transitional arrangements

Planning permissions are valid for 3 years or another specified period and local planning authorities may have granted:

• planning permission in relation to sites that were not within PSZs at the time
• outline planning permission in relation to such sites but not yet determined any reserved matters or other detailed consent required

The Secretary of State is not seeking the:

• revocation or modification of an unimplemented planning permission during its lifetime
• refusal of detailed consent on PSZ grounds when provided that such an approval does not result in a greater number of people on the site than would have been appropriate for the type of use for which the outline permission was granted

Alternatively, however, if a planning permission has not been implemented by the time it expires, any application for an extension of the permission should be considered in the light of the general presumption and development permissible within PSZs guidance.

Development not requiring planning permission

PSZ policy has full effect only when an application for planning permission is made.

Local planning authorities should also have regard to PSZ policy when considering and commenting on proposed development for which they are not the determining authority, such as:

• Crown development
• overhead power lines
• some forms of permitted development and orders made under the Planning Act 2008 and Transport and Works Act 1992

Where the exercise of permitted development rights would encourage more people on to land within a PSZ, the local planning authority should consider whether an article 4 direction, made under the Town and Country Planning (General Permitted Development) (England) Order 2015 is appropriate to require a planning application. Relevant circumstances might include the temporary use of land within a PSZ for the holding of a market or its proposed use as a caravan site.

Transport infrastructure

Although transport infrastructure within PSZs is typically used by any one person for only a short period at a time, a large number of people can be using a particular facility at any particular time.

The density of occupation of a six-lane motorway or a mainline railway, averaged over a day, is similar to that of a housing development.

Transport infrastructure is therefore considered for PSZ policy purposes as if it is residential, commercial or industrial development.

As with those forms of development, the Secretary of State does not consider it necessary to remove existing transport infrastructure from within PSZs. However new transport infrastructure should not be permitted within the PSZs, such as:

• railway stations
• bus stations
• park and ride schemes

This is because they would result in a concentration of people for long periods of the day.

The planning of new transport links requires careful consideration.

Although people passing along a transport route are likely to be within the PSZ for only a very small part of the day, the average density of occupation within the zone may be significant, and as high as that for fixed development.

Individual schemes should therefore be considered on their merits.

Proposals for major roads and motorways should be carefully assessed in terms of the average density of people that might be expected to be exposed to risk.

Careful attention should also be given to the location of major road junctions and to related features such as traffic lights and roundabouts, which may lead to an increase in the number of stationary vehicles within a zone.

Low-intensity transport infrastructure, such as minor or local roads, can be permitted within PSZs.

Official searches

Local planning authorities whose areas include either a PSZ or part of a PSZ should ensure that the associated restrictions on development are entered in the Register of Local Land Charges.

Purchase notices and compensation payable by local planning authorities

The refusal of planning permission on PSZ policy grounds does not carry with it an automatic entitlement to compensation.

There may be a right to compensation under a purchase notice, issued by the owner of the site or property to the local planning authority if a site or property is incapable of being put to any alternative beneficial use as a result of it being within a PSZ.

Where permission for development is refused, or conditions are imposed, a local planning authority may have to acquire the site under the purchase notice provisions in sections 137 to 144 of the Town and Country Planning Act 1990, or pay compensation under section 144(2) of that act.

Similarly, if planning permission is revoked or modified, or if permitted development rights are withdrawn by a direction under article 4 of the Town and Country (General Permitted Development) (England) Order 2015 and planning permission is refused or granted subject to conditions, a local planning authority may incur expenditure under sections 107, 108 or 279 of the 1990 act.

In these circumstances, if the action which gives rise to a compensation claim has been taken solely on PSZ policy grounds, these arrangements apply.

Airports subject to part 3 of the Airports Act 1986

Section 61 of the 1986 act provides for the local planning authority to recover from the airport operator compensation which the authority has become liable to pay.

This provision applies if the compensation liability results from:

• a planning decision which would not have been taken

or

• from an order under section 97 of the Town and Country Planning Act 1990, which would not have been made but for the need to secure the safe and efficient operation of the airport, prevent persons or buildings from being struck by aircraft using the airport

or

• the need to secure the safe and efficient operation of apparatus which is owned by the airport operator and provided for the purpose of assisting air traffic control or as an aid to air navigation

Section 61 of the 1986 act also provides for the purchase of land by the operators of airports subject to Part 5 of that act where a purchase notice is served.

Airports not subject to Part 5 of the Airports Act 1986

Where a local authority or privately owned airport is not subject to Part V of the Airports Act 1986, section 61 does not apply.

Local planning authorities may wish to seek specific deeds of indemnity from the owners of any such airports against liability under the purchase notice and compensation provisions of the Town and Country Planning Act 1990 so that the airport owners will be the bodies to whom any land acquired under a purchase notice will normally be conveyed.

Public safety zone maps

The aerodrome operator will produce the PSZ maps and physical copies of maps, sending them to:

1. The local planning authorities whose areas are affected by them.
2. To the CAA.

Incorporation of PSZs into development plans

Local plans should identify that:

1. PSZs have been established for a particular airport.
2. That there is a general presumption against most kinds of new development and against certain changes of use and extensions to existing properties within the zones, as described.
3. The extent of PSZs should be indicated on local plan maps.

Military aerodromes

The Ministry of Defence is responsible for PSZ matters at military aerodromes, although there are no such zones currently in use at these sites.

Review period

The policy will be reviewed on a 10-year basis using the latest accident data from industry sources.