The phrase "an existing runway" is correct and usable in written English.
It can be used when referring to a runway that is already in place or operational, often in the context of aviation or construction.
Example: "The airport plans to expand its facilities by adding a new terminal next to an existing runway."
Alternatives: "a current runway" or "an operational runway."
In December, the Department for Transport confirmed that the commission's shortlisted options – new runways at Heathrow or Gatwick, or extension of an existing runway at Heathrow – were "viable".
Ministers are considering the proposal alongside two plans for the expansion of Heathrow – the building of a third runway or the lengthening of an existing runway.
The Airports Commission examined three options in a report published last year: a third runway at Heathrow, which was the preferred choice, the extension of an existing runway at Heathrow, or the building of a second runway at Gatwick.
The Airports Commission is due to make its recommendation this summer on whether to build a third runway at Heathrow, a second runway at Gatwick, or whether to extend an existing runway at Heathrow.
The Davies commission favoured three options: a third runway north-west of Heathrow, the airport's preferred choice; a second proposal to double the length of an existing runway at Heathrow, put forward by the unconnected Heathrow Hub group; and a second runway to the south of Gatwick.
Transport secretary Chris Grayling has acknowledged that any of the three options on the table – new runways at Heathrow or Gatwick, or extending an existing runway at Heathrow – would be controversial but would "open up new opportunities for Britain" as it adjusted to Brexit.
The Airport Commission report by Sir Howard Davies, due after the General Election, has shortlisted three options for increasing air capacity in London - lengthening Heathrow's existing runway, building a third runway or building a second runway at Gatwick.
Construction of a solid surface runway began in late 1939 and in 1940 it was proposed to extend the existing runway to a length of 1,550 yards (1,417 m).
The commission shortlisted three options: Gatwick Airport's proposal for a new runway to the south of the existing runway, Heathrow Airport's proposal for one new 3,500m runway to the north-west of the existing airport, and Heathrow Hub's proposal to extend the existing northern runway to at least 6,000m.
The Davies commission will publish an interim report by the end of 2013, with ideas on how to improve the use of existing runway capacity over the next five years and an assessment of what is needed to maintain the UK's global hub status.
The Davies shortlist options: A 3km runway to the south, costing around £10-13bn, far enough from the existing runway to be operated independently and so able to expand capacity dramatically.
