London City Airport Feels the Earth Move

On 2 July 2009, the earth moved for London City Airport. No, really.

London City Airport’s runway designators ‘28’ and ‘10’ are the abbreviated magnetic runway headings of 280° and 100°. These headings are used to identify the direction in which the runway was being used.

As the earth slowly orbits in a circular path, the direction from a fixed object, like the airport’s runway, to magnetic north is constantly moving.

The direction of magnetic north decreases by approximately eight minutes of a degree every 12 months, therefore every seven and a half years it is altered by one degree. The amount of annual change depends on where in the world the fixed object is located.

In the UK, there is a directional change moving west which causes the runway heading to decrease. This means that the magnetic heading of the airport’s runway has moved by almost 10°since being established in 1987. Consequently last night (1/2 July) London City Airport’s runway designation was changed to 270° and 090°, abbreviated as ’27’ and ‘09’.

A team of staff and contractors worked throughout the night to change the airport’s signage and paint markings. In addition a comprehensive document change took place, whereby all official charts and reference material were amended to reflect the change.

Pilots flying into London City Airport today will notice the new markings on the runway whilst staff on the ground indeed felt the earth move under their feet.

It may be at least 50 years before the runway designation needs to change again at London City Airport.