Earlier this week, the UK government announced its support for the expansion of Heathrow Airport into a "hub airport of the future." The country has spent a number of years considering how best to increase its airport capacity and the decision signals the direction it will pursue.

Heathrow's operating company, LHR Airports, says the expansion would make Britain "the best connected country in the world," adding 40 more long-haul destinations from the airport, including Wuhan (China), Osaka (Japan) and Quito (Ecuador), and increasing its domestic services. The airport is already one of the busiest in the world and operates at 99 percent capacity. That capacity would be increased to 740,000 "flight movements" annually, up from just over 470,000 last year.

The so-called "Heathrow Vision" is aimed at furthering Heathrow's position as a hub airport for the UK, Europe and the rest of the world. Hub airports are those through which carriers concentrate traffic for connections to elsewhere, and Heathrow's expansion is seen as a way for it to stay competitive against the likes of those in Paris, Frankfurt, Amsterdam and Madrid.

Earlier this year, Grimshaw was chosen as the architect to realize the Heathrow Vision in the event that the airport's expansion plans come to fruition. It triumphed over Zaha Hadid Architects, HOK and Benoy for its "visionary concept designs, which pushed the boundary of what an airport could and should be." LHR Airports says Grimshaw's sustainability and affordability considerations were also a factor in its success.

The plans, which are said to be "continually evolving," are based on the addition of a third runway and a sixth terminal to the existing facilities at Heathrow. A proposed length of 3,500 m (11,500 ft) would allow the runway to accommodate the largest airplanes in operation, such as the Airbus A380.

The existing Terminal 5 will be combined with the new Terminal 6 west to create "Heathrow West," while a new "Central Terminal Area" will see the airport's current Terminal 2 expanded to become "Heathrow East" and what is now Terminal 3 converted into a new hotel and facilities for passengers and businesses. A"toast rack" formation of satellite terminals between the new East and West areas will help to improve efficiency.

Elsewhere, a new track transit system will help to reduce connection times between terminals, while new mitigation measures and technology will be employed to reduce the number of people who are affected by "significant noise" by 200,000.

The expansion of Heathrow is one of a number of options for increasing and optimizing the UK's air capacity. Other possibilities include the expansion of Gatwick and Stansted airports and the construction of a new airport on an artificial island in the Thames Estuary. After a two-and-a-half year £20 million study, though, the UK's Airports Commission found that developing Heathrow would be the most effective course of action, stating in its report last year:

"Overall, the analysis suggests that the strongest benefits for the UK economy are likely to come from focusing capacity where demand is strongest: be that from freight users, leisure passengers, business travellers or the international transfer passengers needed to support a dense long-haul network. In each case, the highest levels of demand are seen at Heathrow."

The plans must face a public consultation – and likely a number legal challenges – before a final decision is made. Assuming they go ahead, though, the expanded Heathrow is slated to open in 2025.

The video below provides a CGI fly-through of the current designs.

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