Comment

Primitive navigation

The story as I first heard it (another telling is here) goes something like this:

To the west of London are two airports: Heathrow and Northwood. Their runways are parallel, and a little way out under the flight path of each runway stands a pair of gasometers that pilots use to line up their approach.

One night though, the pilot of a jumbo jet mistook Ruislip's gasometer for Heathrow's, and attempted to land on the much shorter civilian runway.

To avoid a repeat occurrence, the word 'NO' has been painted on the Northwood gasometer so that pilots know they should re-check their approach.