Drift of Magnetic Pole

Some Radio Amateurs fail to take into account the variance between magnetic and true north when aligning their beam antennas.

Recently an airport in Essex, England, had to rename one of its runways due to magnetic drift.

A BBC news report says

Stansted Airport in Essex has renamed its 3,000m (9,750ft) runway because the position of the Earth's magnetic North Pole has moved.

The runway was known by pilots and air traffic controllers as 23/05 because of its location and compass heading.

The magnetic North Pole drifts naturally, and every 50 years its position alters significantly.

Managers at Stansted decided they must call the runway 22/04 to reflect the new position and bearing.
Trevor Waldock, head of airside operations, said: "We've had to make this change due to the Magnetic North Pole slowly drifting on the Earth's surface but our runway remains in a fixed position.

Read the full BBC News report 'Runway rename as North Pole moves' at
http://news.bbc.co.uk/1/hi/england/essex/8136307.stm