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Easterly alternation

 

Project Update 

The project team completed a period of community engagement in September 2024, visiting neighbouring communities that will experience a change from Easterly Alternation. We would like to thank those that visited our events and provided the team with useful insights.

The planning proposal has now been completed and submitted to the London Borough of Hillingdon. Hillingdon will now complete a public consultation on the proposal submitted, which will run from 14 November 2024 – 16 January 2025. 

Details about the application and how to respond to the consultation can be found here on Hillingdon’s website - London Borough of Hillingdon - Planning

Included in the planning proposal is further information about planning, design, environmental assessments, as well as details about the noise mitigation offer.

Heathrow hopes to receive a decision on the planning proposal by Spring 2025.

 

Introduction

We have developed proposals for the first phase of a project to enable easterly departures on Heathrow’s northern runway. Easterly Alternation is being brought forward following the Government’s historic decision to end the Cranford Agreement.​

​This project consists of two elements:

1.     Ground infrastructure changes:
  • Taxiway adjustments: Improving the ground routes for aircraft between terminals and the northern runway, to facilitate full runway alternation when Heathrow Airport is operating in an easterly direction (towards London)
  • Noise barrier: Constructing a new noise barrier at Longford to mitigate noise impact

This element of the project will require planning permission from London Borough of Hillingdon under the Town and Country Planning Act 1990.

2.     Civil Aviation Authority (CAA) procedures: 

The second element will require Heathrow to comply with the CAA airspace regulatory procedures to utilise the current airspace structure for full runway alternation during easterly operations.

The two elements of the project are required to enable Heathrow to alternate runways when on easterly operations in the same way we already do for westerly operations. It will also provide more equitable distribution of aircraft noise for our local communities.

Our proposals will not change the number of aircraft flying in and out of Heathrow. They are also not a pre-cursor to any potential airport expansion. This project is to support the end of the Cranford Agreement and allow more equitable distribution of noise for local communities.

To support this project, we recently held a series of engagement events in the local community.

If you were unable to attend one of our events and have questions for the project team, please contact the team by email communityrelations@heathrow.com.


 

Operations at Heathrow

For safety and performance reasons aircraft typically take off and land into the wind. The aircraft’s wing relies on the speed of the air moving over it (airspeed) to lift it off the ground.

Today, for 30% of the time we operate on Easterly operations, aircraft generally land on the northern runway and depart from the southern runway.

Aircraft currently only depart to the east from the northern runway in exceptional circumstances, due to the legacy of the Cranford Agreement.

Picture detailing the alternation patterns at Heathrow, showing that for 70% of the time Heathrow operates on westerlies and 30% of the time on easterlies. Westerly is when the wind blows from the west, and easterlies are when the wind blows from the east.

Runway alternation

During the day, when planes are landing and taking off towards the west (Westerly operations), we alternate the use of our two runways to provide local communities with respite.

The alternation pattern means that for part of the day we use one runway for landings and the other for take-offs, then at 3pm, we switch over.

At the end of each week, we switch completely so that communities get respite from planes in the morning one week and in the evening the next.

This project will support us in alternating between our runways when on easterly operations.

Animation of proposed easterly operations with runway alternation.
Proposed easterly operations with runway alternation.

Predictable respite

Easterly alternation will bring predictable periods of respite from aircraft noise when Heathrow is operating on easterlies. Aircraft noise will be shared more equally – as it is today when we are on westerly operations.

This means we can offer our neighbours a schedule that will detail periods of flights overhead and periods of noise respite.

The image shown is an extract from the westerly alternation schedule. Once we are further along in the project we can provide further timetables for easterlies.

An extract from the westerly alternation schedule, to show an example of what we will be able to provide for easterlies in the future when easterly alternation is in place.

Environmental impact assessment

The ground infrastructure changes require an Environmental Impact Assessment to be submitted with our planning application. This is underway and our emerging information shows that there will be more predictable periods of respite for our local communities with noise levels shared more equitably around the airport. 

Some communities will experience new noise overhead, as they were not previously overflown when Heathrow is on easterly operations, due to the Cranford Agreement.

Communities who are currently overflown when on easterly operations will experience a decrease in number of flights overhead each day, as the redistribution of existing flight paths will be further spread out over more communities.

Open map
This diagram shows which communities will have changes in noise and respite as a result of easterly alternations.
Respite during easterly operations with runway alternation

Ground infrastructure changes

Our proposals require some airport ground infrastructure changes to be made.

These include adjustments to the taxiways leading to the northern runway and the construction of a new noise barrier near Longford, which could be between 5-7 metres high.

Part of the noise barrier will replace an existing acoustic barrier running alongside Wright Way and a fence which marks the boundary of the Terminal 5 POD car park. The images below show the location of the noise barrier and a visualisation of what the noise barrier might look like when constructed.

A map defining the noise barrier outline
Noise barrier outline
Image shows a example of a winter noise barrier. Appears like a fence within shrubbery.
Noise barrier in winter
Image shows a example of a noise barrier in summer. A barely noticable fence within thick shrubbery.
Noise barrier in summer

The Cranford Agreement

The Cranford Agreement was established in 1952 as a verbal agreement between the Government and Cranford, a village at the eastern end of the northern runway.

The agreement prevented aircraft from taking off over the village except in exceptional circumstances. For example, we took off over Cranford during the Covid-19 pandemic when we operated on one runway.   

Following a consultation, the Government ended the Cranford agreement in 2009, to provide more predictable periods of noise respite to all communities surrounding Heathrow.  

Although the Cranford Agreement has ended, we have not yet introduced Easterly Alternation on the northern runway because the airfield requires our proposed infrastructure changes to achieve this.  

In 2013 we made an application to the London Borough of Hillingdon for the same project, this was granted planning permission from the Secretary of State in 2017.  However, we didn’t go ahead with the works then, because of the proposals for the third runway.  The previous planning application has now expired.

Next steps

Following our community engagement in September 2024, we submitted a planning proposal to the London Borough of Hillingdon in October 2024. Hillingdon will complete a public consultation on the proposal submitted and we hope to receive a decision from Hillingdon by Spring 2025.

If you have any questions about the Easterly Alternation project, please contact communityrelations@heathrow.com.