Under the flight path
When planes take off, they have to follow specific routes which were set by the Government. These routes, which are 3km wide, are designed to make sure planes avoid flying over areas where lots of people live until they reach a certain height.
At Gatwick those heights are either 2,798 or 3,798ft depending on which flight path the aircraft is on. These heights might seem a little odd but they take account of the fact that Gatwick is 202ft above sea level. ATC measures height above sea level (altitude) which means they are looking for aircraft to reach 3,000 or 4,000ft before they can direct them off the flight path towards their destination.
The technical name for these special flight paths for take-off is ‘noise preferential routes’ (NPRs). They were set by the DfT several decades ago.
Taking off and the importance of wind direction
Another basic aspect of aviation safety is that planes need to land and take off into the wind. They can take off in the same direction as the wind, but this is only allowed if it’s wind up to 5 knots, which is little more than a breeze.
Most of the time at Gatwick, the wind comes from the west so most of the time they’ll fly towards the west.
Therefore, the Government set the take-off flight paths for when the wind is blowing from the west. Of course, we can’t control the direction of the wind. Because of this, the Government has also set take-off flight paths for the opposite wind direction from the other end of the runway, as the map above shows.
What does this mean locally?
It means that on average, about seven out of ten take-offs head towards the west and only three out of ten take-offs go east.
The split in take-off direction is almost completely dependent on the wind direction and speed, and so varies from year to year and month to month. In fact, the length of time that the runway operates in one direction can vary from a few hours to a few months: it all depends on the weather.
If you live under one of these take-off flight paths, then you will probably hear some noise when that particular flight path is being used. If you live beyond the flight path – past the point where the plane reaches 2,798 to 3,798ft – then you might sometimes hear noise when the plane leaves the flight path to head towards its destination.
If you live alongside (but outside) a flight path, you might hear noise if a plane flies outside the flight path. This can happen if ATC tells a pilot to leave a flight path for an operational reason (such as to avoid bad weather). We take ‘track keeping’ (staying on the flight path) very seriously and 98% of Gatwick’s aircraft are ‘on-track’. On this website we tell you what we are doing about this type of noise and how you can find out more information or contact us if you need to.
Other local procedures
There are also a few Gatwick-specific operating procedures. For example, pilots have to avoid flying over Horley and Crawley once they take off. They also have to stay above 2,798 ft over Crawley, East Grinstead, Horley and Horsham and over 1,798 ft over Lingfield when landing.
From 19 July 2012 to 12 October 2012, we are holding a public consultation on proposals to accurately refine the existing aircraft departure routes from Gatwick Airport within the next five years.
Noise preferential routes (NPRs) are set by the Department for Transport for all UK airports, including Gatwick. This means that all aircraft leaving Gatwick follow NPRs up to a height of 3,000 to 4,000 ft as they leave the airport.
Through our consultation we'd like your views on the proposed refinements to the departure routes within NPRs which will eventually replace the current standard departure routes from the airport. The new routes will be more accurately defined using improved navigational cababilities (P-RNAV).