Shaping the future
Have your say on London Gatwick’s Route 4 Airspace Change
Stage 3 Consultation Summary Document: HTML version
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Introduction
The UK’s airspace was designed in the 1950s using now outdated forms of navigation technology. This technology is being phased out as part of a government-led drive to modernise airspace in the UK.
Due to these changes, all UK airports have been required to review and, in some instances, make changes to their airspace design so they can adopt new navigational procedures which use modern, satellite-based technology.
For London Gatwick, this has meant undertaking an airspace change process to introduce the new navigation procedures on all nine of the departure routes from its Main Runway.
Want to know more about airspace modernisation in the UK?
You can learn more about the transition from ground-based to satellite-based navigation procedures in Section 2.3 of the Main Consultation Document.
This process began in 2012 and involved engagement and consultation with local communities and stakeholders. Following approval from the Civil Aviation Authority (CAA) – the UK’s airspace regulator – all nine departure routes started using the new navigation procedures in 2013.
However, due to legal and regulatory challenges, the new navigation procedures were withdrawn on one of London Gatwick’s departure routes, known as Route 4, in 2018.
Want to know more about the history of Route 4?
You can learn more about the history of Route 4 in Section 1.1 of the Main Consultation Document.
Since that time, London Gatwick has undertaken extensive work to re-introduce satellite-based navigational procedures to Route 4. This work is essential because the ground-based technology which underpins conventional navigation is being phased out.
To make changes to its airspace, London Gatwick must submit an airspace change proposal (ACP) and follow a detailed, seven-stage process set out by the CAA.
London Gatwick held a public consultation, which was a chance for you to have your say on the shortlisted options for the future of Route 4. Your feedback will inform which option is submitted to the CAA for formal approval.
Following early engagement with community representatives and industry stakeholders under Stages 1 and 2 of the process, London Gatwick has now reached Stage 3. At Stage 3, London Gatwick is required to consult with the public and stakeholders on the options it has shortlisted during the previous stages.
This Summary Document provides a short introduction to this ACP, including the four options that have been shortlisted, and an explanation of the process being followed.
More detailed information about this ACP is provided in the other consultation materials associated with this public consultation, including the Main Consultation Document and Full Options Appraisal (FOA).
Further information and tools are available on the website: route4acp.co.uk
This consultation is now closed.
If you have any questions, you can contact us via email: LGWairspace.Rte4@gatwickairport.com or freephone: 0808 303 4560
What to know more about our work to date on this ACP?
You can learn more about earlier stages in the process for this ACP in Section 2.6 of the Main Consultation Document.
Background to this consultation
What is airspace?
Airspace is the invisible infrastructure in the sky which helps aircraft navigate safely. This includes the flight paths that aircraft use when taking off, flying and landing, as well as the holding patterns used by aircraft before landing.
Typically, airspace in the immediate vicinity of an airport is controlled by that airport. Within this airport-controlled zone, airports generally operate a series of pre-defined departure routes, known as Standard Instrument Departures (SIDs), that departing aircraft must follow, unless directed otherwise by Air Traffic Control (ATC).
These SIDs are aligned to Noise Preferential Routes (NPRs), which are set by the Government and are designed to minimise noise disturbance to local communities. London Gatwick’s SIDs are designed to comply with the NPRs until they reach above a certain altitude.
What to know more about how airspace works?
You learn more about airspace in Section 2.1 of the Main Consultation Document.
About Route 4
Route 4 is one of nine SID routes for aircraft taking off from London Gatwick. It applies to aircraft taking off to the west from the Main Runway but ultimately heading east on their journey. Soon after take-off, aircraft flying Route 4 turn 180 degrees northwards and head east, flying in the vicinity of South Holmwood, Leigh, Redhill and Reigate before flying on towards their final destination.
The nine SIDs at London Gatwick (and their associated NPRs) are shown in the image below.
| Stage 1 Define | Assess requirement | |
| Design principles | ||
| DEFINE GATEWAY | ||
| Stage 2 Develop and Assess | Options development | |
| Options appraisals | ||
| DEVELOP AND ASSESS GATEWAY | ||
| Stage 3 Consult/ Engage | Consultation/engagement preparation | |
| CONSULT/ENGAGE GATEWAY | ||
| Commence consultation/engagement | ||
| Collate & review responses | WE ARE HERE | |
| Stage 4 Update and Submit | Update design | |
| Submit proposal to CAA | ||
| Stage 5 Decide | CAA assessment | |
| CAA DECISION | ||
| Stage 6 Implement | Implement | |
| Stage 7 PIR | Post implementation review |
Why this ACP is needed
When the UK’s airspace was designed in the 1950s, ground-based beacons acted as the main form of navigation technology. However, a government-led drive to modernise aircraft navigation and gradually phase out ground-based forms of navigation is currently underway.
For London Gatwick, this means introducing new satellite-based navigation procedures on all its arrival and departure routes so that aircraft can use new GPS-style technology to replicate the existing route positions.
London Gatwick introduced the new navigation procedures on all nine of its departure routes following an airspace change process that began in 2012. This process included engagement and consultation with communities and stakeholders.
However, due to regulatory and legal challenges, the new navigation procedures were withdrawn on Route 4 in 2018.
Since then, London Gatwick has undertaken extensive work to re-introduce satellite-based navigational procedures to Route 4.
What are the potential impacts of this ACP?
The reintroduction of satellite-based navigation procedures for Route 4 will deliver benefits such as:
- Enabling further improvements in aircraft and passenger safety;
- Delivering targeted noise reduction for communities by avoiding built up areas and providing opportunities for wider track dispersal and relief;
- Limiting and seeking to reduce, where possible, the environmental impact on local communities; and,
- Providing long term predictability and greater compliance with the flight paths set by Government – known as Noise Preferential Routes (NPRs).
Different communities will be differently impacted by the four options we are consulting on. You can find out more about the impacts of the different options on page 15 of this document, and find out more about the impact of each option on a given address using the postcode look-up tool on our Citizen Space site, route4acp.co.uk.
How the process works
The Civil Aviation Authority (CAA) has responsibility for deciding whether to approve changes proposed to the design of airspace in the UK.
Proposals to change airspace design must follow a detailed process as set out in the CAA’s CAP1616: The Process for Changing the Notified Airspace Design.
The process requires the organisation proposing the change (in this case London Gatwick) to engage stakeholders and the wider public at key stages of the process to explain the proposed changes and gather feedback.
In the case of this ACP, four route options for the future operation of Route 4 have been shortlisted after earlier engagement with community representatives and industry stakeholders at Stages 1 and 2 of the process.
London Gatwick is now at Stage 3, where it has carried out a Full Options Appraisal (FOA) of the shortlisted route options and completed a public consultation to gather feedback from communities and stakeholders on the route options presented.
This feedback will help London Gatwick make informed decisions about the proposals ahead of its submission at the end of Stage 4.
The following diagram provides a summary of the key stages of the ACP process.
Want to know more about how the ACP process works?
You can find out more about the different stages of the ACP process in Section 2.5 of the Main Consultation Document.
What was not within the scope of this consultation
This ACP is distinct from the Northern Runway Project. It only concerns re-introducing satellite-based departure procedures for Route 4 from the Main Runway, and it is not interdependent with the Northern Runway Project.
Changes to the Route 4 Noise Preferential Route (or other NPRs) were outside the scope of this ACP and not part of this consultation, because noise controls are set by Government. After this airspace change is implemented, the Government is expected to assess the impact and set the appropriate noise controls.
Want to know more about how London Gatwick developed its shortlisted options?
To read about this earlier work and see the full list of stakeholders who took part see the Design Principles Report and Design Engagement DocumentDocument, which are available to download on our Citizen Space site.
The shortlisted options
Following engagement with community representatives and industry stakeholders during Stage 1 and 2, London Gatwick sought feedback on four shortlisted options as part of this public consultation.
Want to know more about constraints on the available options for Route 4?
You can find out more about the constraints on the options for Route 4 in Section 4.2 of the Main Consultation Document.
Option A
Option A aims to closely replicate the existing conventional procedure. Aircraft depart straight ahead, then turn at waypoint KKW02, following a path designed to match the conventional route as closely as possible. After the initial turn, aircraft proceed through waypoints KKE09 and KKE11, before routing via ACORN to their destination. This is the only option that retains the ACORN waypoint.
Click on the map below to watch an animation of this option.
Option B
Option B is based on the previous satellite-based navigation procedure introduced in 2016 but keeping the straight portion after the turn as per the existing conventional procedure, unlike Option D (below). Aircraft follow the same initial departure and turn at waypoint KKW02, then proceed through NEW09 and NEW11 waypoints towards SUNAV.
Click on the map below to watch an animation of this option.
Option C
Option C introduces as much dispersion in the turn as we can in line with feedback received during Stage 2 of the ACP process. It features three sequential turn points, spaced 400m apart and rotated periodically to vary departure paths. After the chosen turn, aircraft converge at waypoint NEW09 and continue through NEW11 to SUNAV. This option increases variability in flight paths, but this variation will need to take place at pre-agreed periods for safety and operational reasons.
Click on the map below to watch an animation of this option.
Option D
Option D replicates the satellite-based navigation procedure as published in 2016, including a tighter initial turn at waypoint KKW02 resulting in more pronounced track overshoot. After the turn, aircraft pass through waypoints WPT09 and WPT11, then adjust left at KKE15 before heading to SUNAV. The route tracks further south than other options.
Click on the map below to watch an animation of this option.
Discover more using London Gatwick’s postcode lookup tool
To help you understand the route options in greater detail, an online tool is available to illustrate the different impacts of each option relative to where you live.
Assessing the options
Assessing the options
Establishing a baseline
A key part of the airspace change process is the options appraisal process, which comprises systematic qualitative and quantitative analyses of the options against a range of criteria. Options appraisal is used as a tool throughout the airspace change process: an Initial Options Appraisal was conducted during Stage 2 to refine the options from an initial longlist to the current four shortlisted options, a Full Options Appraisal (FOA) has been conducted during Stage 3 to analyse and compare the shortlisted options against several criteria and a Final Options Appraisal will be conducted, following consultation, during Stage 4 on the final selected option.
For most ACPs, the shortlisted options are compared against the current operation, which acts as a ‘baseline’ for the purpose of making a comparative analysis of the relative impacts of each option.
Want to know more about the baseline for this ACP?
You can find out more about how London Gatwick defined the baseline for this ACP in Section 3 of the Main Consultation Document.
Want to know more about the summary of the options appraisal?
You can find a summary of the options appraisal in Section 5 of the Main Consultation Document.
However, because maintaining the current operation of Route 4 is not a viable long-term option (as the ground-based beacons it relies upon will soon be removed from service), it is necessary to define a ‘do minimum’ option to act as the baseline for this ACP.
The do minimum baseline for this ACP continues use of the current conventional route but using satellite-based technology as a substitute for the conventional navigation procedures. You can learn more about this substitution process in the Civil Aviation Authority’s CAP1781 Guidance.
Comparing the options
Extensive work has been undertaken to identify the potential impacts (positive and negative) of each of the options associated with this ACP against a range of criteria, including noise, air quality, greenhouse gas emissions and fuel burn.
The FOA provides a detailed assessment of the expected benefits and impacts of the proposed route options. The FOA is available to view at route4acp.co.uk.
Want to know more about the technical studies undertaken for this ACP?
You can find out more about the technical studies undertaken for this ACP in Section 5 of the Main Consultation Document.
Take part and have your say
Take part and have your say
This consultation has now closed.
It ran from Tuesday 20 January 2026 until Tuesday 28 April 2026.
To ensure consultation activity is targeted towards people living, working or otherwise using the areas likely to be most affected by this ACP, London Gatwick has employed a zoning system to identify additional stakeholders and members of the public that have not been engaged with as part of Stage 1 or 2 of the process.
The mapping of these zones has been informed by noise contours generated within the Full Options Appraisal (FOA) with additional buffer areas applied as outlined in this table.
The three consultation zones
Want to know more about how we’ve defined our consultation zones?
Find out more in section 8.2 of the Main Consultation Document.
| Zone | Definition |
|---|---|
| Zone 1(Z1) | Zone 1 covers areas experiencing average noise levels of 51dB or higher during the day and 45dB or higher at night, based on historical runway usage data, and includes 5,200 residential and business addresses. |
| Zone 2(Z2) | Zone 2 covers areas experiencing 20 or more overflights exceeding 65dB during the day and 10 or more events exceeding 60dB at night, not already in Zone 1, and includes 6,130 residential and business addresses. |
| Zone 3(Z3) | Zone 3 covers areas potentially affected by the ACP based on Route 4 overflight data, including 75,314 residential and business addresses. |
Conclusion
From a safety and operational perspective, there is no difference between the options. However, because Option D performs best against the environmental criteria of the options appraisal, Option D has been selected as the preferred option.
While Option D offers the greatest potential environmental benefits, London Gatwick has no opinion on which of the options is delivered. London Gatwick has followed the CAA’s guidance and fulfilled its statutory duties with regards to the airspace change process.
This public consultation is a chance to have your say on the shortlisted options for the future of Route 4. Your feedback is important because it will inform which option is submitted to the CAA for formal approval. On the next page, you can discover how to take part and have your say.
Next steps
Share your views
This consultation has now closed.
The deadline for submitting feedback was Tuesday 28 April 2026.
Where to find more information
Detailed information about the proposals is available on the website: route4acp.co.uk
Visit one of our deposit points
The key consultation material was available to view (free of charge) at the following deposit locations during the consultation period.
| Venue | Address |
|---|---|
| Dorking Library | St Martin’s Walk, Dorking RH4 1UT |
| Reigate Library | Bancroft House, Bancroft Road, Reigate RH2 7RP |
| Horley Library | 55-57 Russell Square, Victoria Road, Horley RH6 7QH |
| Edenbridge Library | The Eden Centre, Four Elms Road, Edenbridge TN8 6BY |
Next steps
Now the consultation has closed, London Gatwick will carefully consider all the feedback and further refine its proposals in response to the comments received.
Stage 4
During Stage 4, London Gatwick will update the designs, confirm a preferred option and consider if it needs to make any final changes to it based on the feedback it has received. London Gatwick will then complete the Final Options Appraisal and assess the need for additional consultation ahead of submitting the final ACP to the CAA. London Gatwick will also submit a report which explains how it has given due regard to consultation feedback.
Stage 5
At Stage 5, the CAA will review and assess the final ACP and may request further information or clarification from London Gatwick before making a decision. The CAA can also call a public evidence session on the ACP. The CAA will decide whether to approve the final ACP, if it is not first called in by the Secretary of State. Any final decision may be subject to modifications or conditions.
Stage 6
At Stage 6, if the ACP is approved, the proposal will be implemented.
Stage 7
At Stage 7, a Post Implementation Review will be undertaken by the CAA (usually around 12 months after implementation) to determine if the ACP has produced the intended outcomes.
Any questions?
You can contact London Gatwick with questions about this ACP, or request assistance in responding to the consultation, via the following channels:
Website: route4acp.co.uk
Email: LGWairspace.Rte4@gatwickairport.com
Freephone: 0808 303 4560
Freepost: Freepost ROUTE 4 CONSULTATION
Glossary
Glossary
Airspace Change Proposal (ACP)
Airspace change proposals are requests from a ‘change sponsor’, usually an airport or a provider of air navigation services (including Air Traffic Control), to change the notified airspace design. Airspace change proposals must follow the CAA’s airspace change process, known as CAP1616. The process is structured, comprising of different stages and gateways depending on the type of airspace change proposal that has been requested. Both change sponsors and the CAA are involved in the airspace change process, resulting in a final decision by the CAA to approve or reject the airspace change proposal.
Civil Aviation Authority (CAA)
The Civil Aviation Authority (CAA) is the statutory organisation responsible for the regulation of civil aviation in the United Kingdom. Its responsibilities include airspace regulation, air safety, economic regulation and consumer protection. The CAA is a public corporation of the Department for Transport.
Full Options Appraisal (FOA)
The FOA is carried out in Stage 3 of the airspace change process. The options appraisal evolves through three phases: the Initial Options Appraisal, the Full Options Appraisal, and the Final Options Appraisal. The FOA requires the ‘change sponsor’ to develop more rigorous evidence for the design options they plan to consult on. The change sponsor may undertake further work as part of the design process to improve and refine design options before completing the full options appraisal.
Noise Preferential Route (NPR)
A Noise Preferential Route (NPR) is a track line on a map which aims to minimise the number of people overflown by departing aircraft. NPRs at the designated airports are defined by the Government. NPRs have existed since the late 1950s, when the airports were in public ownership. NPRs have historically acted as an important noise control measure with the design of Standard Instrument Departure routes based upon them. The NPRs are defined with an upper limit, in the case of Route 4 the upper limit is 4000 ft.
Post Implementation Review (PIR)
The Post Implementation Review (PIR) is an evaluation that is conducted after changes to airspace have been implemented. The PIR assesses the effectiveness and impact of those changes that have been made, identifies any issues or problems that arose during the implementation, and determines whether the intended objectives of the airspace change proposal have been achieved.
Standard Instrument Departure (SID)
A SID is a predetermined flight path that aircraft follow after taking off from an airport. SIDs are designed to efficiently and safely guide aircraft from the runway to their en-route phase of flight. They typically include specific instructions regarding altitude, headings, and waypoints to follow. SIDs are established at busy airports or in areas where there is a complex airspace structure to ensure orderly and predictable departures. In practice, the choice of SID used is allocated based on a flight plan submitted by the airline.