Taking off and the importance of wind direction
Another basic aspect of aviation safety is that aircraft 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 the wind speed is up to 5 knots, which is little more than a breeze.
Around 70% of the time the wind at Edinburgh comes from the west. So aircraft tend to take-off over Newbridge most of the time. On the occasion that flights do take-off to the east, towards Cramond, the Government has set a take-off flight path known as Standard Instrument Departure (SID).
There are three SID’s used when aircraft are flying to the west and two when they are flying to the east. The first part of a SID is known as a Noise Preferential Route (NPR) and these are 3km wide and are designed to make sure aircraft avoid flying over areas where lots of people live until they reach 3,000ft. At 3,000ft ATC can direct the aircraft off the flight path towards its destination.
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 then you might sometimes hear noise when the aircraft leaves the flight path to head towards its destination.
If you live alongside (but outside) a flight path, you might hear noise if an aircraft 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 aircraft only deviate from the flight path in exceptional circumstances.
Living or working under the approach path
While there are defined flight paths for take-offs, there are none for landings until aircraft are established on the Instrument Landing Systems (ILS), also known as the final approach. On final approach, the aircraft has to line up with the runway from several miles away.
When an aircraft arrives in the local airspace ATC directs each aircraft on an individual course onto the final approach and brings it into land. This is very different to take-off, where aircraft can climb steeply and quickly and turn while it climbs. There is more operational flexibility at take-off than there is in landing.
Many people are not bothered by aircraft noise during the day when ambient noise levels are higher, but they can be affected at night.
There are no restrictions on night flying at Edinburgh Airport. Night time is regarded as the period between 23:00 and 06:00. Generally, there are no passenger services flying at this time, with night flights tending to be mail and cargo operators - such as DHL, TNT and Royal Mail.
Whilst most people will be affected by aircraft noise during the landing and take-off cycle we are also working with airlines to address aircraft noise on the ground.
So what are we doing to reduce ground noise?
Examples of steps we are taking include restricting the duration and location of engine testing, encouraging airlines to taxi with one engine. We’re also working with ATC to cut down the amount of time that aircraft wait to take off, or are taxiing, so that the engines aren’t running for so long.