London’s Heathrow Airport has opened an eight-week consultation on its planned expansion that includes a proposal to add up to 25,000 additional flights a year through more efficient use of its two existing runways, ahead of the opening of a third in 2026.

The London hub announced its Airspace & Future Operations consultation Jan. 8. The public will be given the opportunity to comment on a raft of topics relating to the required airspace changes for an expanded Heathrow and the way in which a three-runway airport would operate.

The consultation, which is open until March 4, also includes the proposed introduction of an interim independent parallel approach (IPA) strategy that could release enough capacity on the existing two runways to allow for an extra 25,000 air transport movements a year. Heathrow’s current annual ATMs are capped at 480,000.

“Releasing capacity using our existing two runways could generate significant economic benefits as the first phase of expansion,” Heathrow said in its consultation documents. The additional flights could be introduced “on a phased basis soon after planning consent is granted, so that the benefits of expansion can begin to be delivered well before the third runway is complete.”

Heathrow estimates the use of IPA will enable it to reduce daily arrival flight delays by up to 13h.

The IPA strategy would involve “some new arrival routes into Heathrow from the holding stacks.” However, Heathrow warned that “some of these flight paths could overfly areas that are not affected by Heathrow arrivals today.”

Only aircraft certified to carry out performance-based navigation (PBN) approaches will be able to use the proposed new flight paths, but Heathrow said that “airline forecasts have demonstrated to us that there will be a sufficient number of certified aircraft to fly the IPA flight paths.”

Heathrow anticipates submitting its request for the required airspace changes to the UK Civil Aviation Authority in 2021, with the aim of implementing the IPA strategy the following year.

After receiving public feedback on the proposal, the airport said it would “test the capacity for, and implications of, early growth.” This will include “implications for terminal and stand capacity, environmental impacts, and how additional passengers would be accommodated in our surface access strategy.” Heathrow will then put forward more detailed proposals in its next public consultation, scheduled to open in June 2019.

The UK Parliament voted in June 2018 to approve the Airports National Policy Statement, which supports the addition of a third Heathrow runway, provided the airport can prove the expansion can be done sustainably. But the plan faces strong opposition from environmental campaigners and local residents’ groups, as well as legal challenges from London mayor Sadiq Khan and local councils.

A final decision on the planned third runway is expected in 2021.

Kerry Reals,