Easterly alternation

During the day we alternate the use of our two runways to provide local communities with respite. However, this currently only happens on westerly operations (when aircraft come into land over London and take off towards Windsor). This is because of the legacy of the Cranford Agreement which was established in the 1950s. Cranford is a village at the eastern end of the northern runway. The agreement prevented aircraft from taking off over the village except in exceptional circumstances and applied when Heathrow was on easterly operations.

This means that during easterly operations, most arriving aircraft will land on the northern runway, with most departures taking off from the southern runway. The agreement favoured residents of Cranford at the expense of other communities such as Windsor and southern parts of Hounslow.

Background

In 2009, the Government announced that the Cranford Agreement should end following consultation with local residents. Heathrow submitted a planning application to the London Borough of Hillingdon in 2013 to construct an additional taxiway at the western end of the northern runway to enable full runway alternation on easterly operations. Planning permission was granted on appeal by the Secretary of State on 2 February 2017. However, on the same day the Government published the draft Airports National Policy Statement (ANPS) which supported the expansion of Heathrow. The airfield design for an expanded Heathrow required a repositioning of the taxiway works, so a new planning application was required which we intended to pursue through the planning process for expansion.

With the decision made at the Court of Appeal in relation to the Airports National Policy Statement on 27 February 2020, and the subsequent Covid-19 pandemic, we paused our expansion plans. However, we have remained committed to airspace modernisation and these plans have been taken forward through an Airspace Change Proposal focused on Heathrow’s existing two runways. Respite for easterly operations remains a key commitment at Heathrow and forms part of these plans for airspace modernisation. Unfortunately, during this time the planning permission for the airfield works required to enable full easterly alternation has expired.

Our application to enable easterly alternation at Heathrow is not related to airport expansion or a third runway. It will be implemented for the existing two-runway operation, and it will deliver on our Heathrow 2.0 commitment to offer fair and equitable distribution of respite from aircraft noise for our local communities when we are on easterly operations. 

Next steps 

To enable easterly alternation, Heathrow will need to submit a planning application to the London Borough of Hillingdon. We are now in the early stages of preparing that planning application. The timescales to deliver easterly alternation are therefore subject to the planning application for repositioning taxiways, the time required to then complete the associated ground works, and the subsequent airspace change process. 

Approval of the application will enable the required ground works to upgrade the taxiway infrastructure. We have submitted our Environmental Impact Assessment (EIA) Scoping Request to Hillingdon and our report is available on their website. The purpose of the report is to provide a summary of technical and environmental information that Hillingdon would expect to see included as part of any planning application submitted to them for the proposed ground works. This will be followed by submission of the full planning application in early 2024. Hillingdon will then need some time to assess the application and make a decision.  We cannot currently be certain about the timeline for approval as our previous application took longer than expected to be resolved, as it was granted on appeal. We are also undertaking some local air quality testing in Longford to support the application’s EIA.

While the ground works will provide the physical airfield layout needed to support easterly alternation, we will also change the way we use the airspace for departures. Therefore, we also need to follow the Civil Aviation Authority’s airspace change process. We are currently progressing this through our existing Airspace Change Proposal to support airspace modernisation. The process takes several years to deliver, and we are currently expecting implementation between 2027 and 2029.  

Easterly alternation will finally bring predictable periods of respite from aircraft noise to thousands of people when Heathrow is operating on easterlies and affected communities will share the burden fairly and equally – as they do today when we are on westerly operations. However, we know that some people will be newly impacted by noise under easterly alternation, and we are doing further work to model and communicate the impact of this.

Any changes require full public consultation, which will currently start around 2025. For more information, please visit our Airspace Modernisation section.