First of all a ‘Go Around’ is actually the same as a takeoff except it starts from an airborne location rather than the runway! It is caused because the plane cannot land for some reason:
One reason is windy weather which may, at the last moment, cause the plane to deviate form the centre of the runway during landing. Or a large gust may alter the speed of the plane so that it is no longer at the correct speed – this can be called “windshear” and most planes are fitted with an automatic warning that it is about to occur, or has occurred.
There are other reasons too; the plane in front is meant to clear the runway quickly after landing so as to make room for the next plane landing. However sometimes the plane already on the runway may not clear as quickly as the Air Traffic Controller had expected and he will instruct the landing plane to “go –around”. This will happen quite a lot at busy airports like London Heathrow where there are only two runways and the planes land less than once per minute in a constant stream. It is perfectly safe and pilots are well trained in performing the maneuver.
Here is a video clip of a jumbo doing a go around in windy weather--
Another reason that pilots go around is when the weather is below the limit for landing. Let me explain; whenever you hear that a plane got into trouble because of “fog” or “bad weather” this is untrue. The plane got into trouble because the pilot broke the rules! It should never happen, and in first class airlines it does not. There are four levels (Categories ) to which a plane can descend depending on the quality of the airport landing radio beam (ILS).
CATEGORY 1 200 ft smaller airports mainly
CAT2 100 ft larger airports that have a lot of planes landing
CAT 3 50 ft major airports
CAT 3 C 0 ft world class airports with a poor weather record
It depends on the facilities available and since it is very expensive to provide CAT 3 equipment, it is only available at airports that can justfiy the cost and where there is often fog or low cloud. Again London is a good example.
So taking the two extremes, a plane landing at a more primitive airport cannot descend below 200 ft ,which is the same height as a 20 story building, unless the runway is in view and all else is correct as well. If there is fog and the pilot cannot see the runway he simply “goes around “ and diverts to an airport where the weather is better- and he will have chosen that airport carefully in advance.
Conversely a plane landing at London Heathrow can land when cloudbase is zero – in other words the pilot never has to see the runway at all! The plane lands, put on the brakes itself, stays down the middle of the runway itself and stops itself without any input from the pilot. Well, he does a few things and of course has to taxi off the runway but the rest is all automatic.
The other categories (2 & 3) are somewhere in the middle as you can see from the table.
To Go Around the pilot does a few things in a certain order
- Applies full power
- Raises the nose to the same as takeoff angle – about 15 degrees above horizontal
- Raises the flaps from landing position to the takeoff position
- Raises the wheels
- Climbs away just like a normal takeoff.
- Raises the flaps and accelerates to about 220 kts just as on a normal takeoff
- Decides whether to return for a second landing or divert to somewhere else.
- Makes an announcement to the passengers to reassure them- sometimes the cabin crew will do this first and then the captain.
So although it seems scary when you think you are about to land and then you don’t, rest assured that it is being done to enhance your safety – not the other way around!