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Heathrow scraps runway bridge plan

heathrow taxiways

Heathrow has revealed its thinking behind the three options put forward for the new north-west runway, which show the runway will not bridge the M25 at its existing level.

Three options for the new runway have been published as part of Heathrow’s public consultation, running for 10 weeks until 28 March.

Bridging over the M25 at its existing level has been scrapped as an option depsite being cheaper than diverting the M25 through a tunnel, as the runway would have to be raised by more than 9m and would require too much fill material. Such a sharp incline would also make it difficult to comply with gradients design standards for aeroplane take off.

Instead the M25 will be moved 150m to the west and lowered by 7m through a tunnel. The runway will be raised by 3m to 5m as it crosses the M25, but it will begin and end at ground level and so the height will vary across the length of the runway.

Runway locations with key

Runway locations with key

The runway will need to be a minimum of 75m wide to accommodate Heathrow’s largest commercial aircraft, an A380 model. Options are being considered for a 3,200m runway but the preferred length remains 3,500m.

Heathrow said it will ramp up its use of its existing runways as soon as it submits its DCO application in 2021, releasing an extra 25,000 flights per year. The new runway needs to deliver 260,000 extra flights per year.

Rival expansion group Heathrow Hub said the proposals showed a lack of detail.

“It is unbelievable that nearly six years into this process, Heathrow are still producing new ideas,” said a Heathrow Hub spokesperson.

“There are no detailed breakdown of costs and how these will be passed on to passengers and airlines. It is a Heath Robinson Plan,” they said, citing the illustrator known for drawing elaborately complicated machines.

Consultation documents show plans for a previously proposed terminal with an innovative canopy structure have been scrapped. Terminal 2 or Terminal 5 will be expanded instead, or a ‘satellite’ terminal structure will be built closer to the new runway.

However, new terminal structures must be built on the “public transport spine” (rail connections running between Terminal 2, 3 and 5). Heathrow believes its revised terminal plans will cut £2.5bn from its original £17bn proposal.

Increased surface access by public transport is crucial to Heathrow’s expansion plans, as strict criteria for traffic levels were set by government as a condition for planning permission.

Worsening air quality as a result of expansion is also a concern: earlier this week London’s deputy mayor for transport Val Shawcross told the Commons transport committee that Heathrow’s third runway would delay London’s compliance with legal air quality targets by five years.

The airport has laid out its plans to become a coach hub, and to help develop the Western Rail Link and Heathrow Southern Rail proposals.

Heathrow Southern Railway, the body behind the plan for a rail link between the airport and the South Western Main Line, executive director Graham Cross said: “Even with the existing two-runway airport, there is an air quality emergency in west London to which road traffic around Heathrow contributes significantly. A third runway will make a southern rail link essential if passengers and airport workers are to access Heathrow without making this crisis even worse.”

The Civil Engineering Contractors Association (CECA) said extra airport capacity is vital for economic growth.

“The publication of today’s [Wednesday’s] consultation enables everyone to have a say on Heathrow’s expansion, thus ensuring that this major infrastructure project delivers real benefit for all,” said CECA director of external affairs Marie-Claude Hemming.

Yesterday Heathrow Airport executive director for expansion Emma Gilthorpe said the consultation would help delivery expansion responsibly.

“We want an expanded Heathrow to be the world’s best airport, ensuring that our country and its future generations have the infrastructure they need to thrive,” she said.


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