Take-off, departure, aircraft take-off

What happens when a plane takes off?

Paola Leibbrandt
16.10.2018
1 picture
4 minutes

An adrenaline rush for many passengers: when an aircraft takes off and you’re pressed back into your seat. But how on earth does this massive machine actually manage to lift itself off the ground? Let us explain precisely what has to be done before a plane takes off.

After the landing is before the take-off

In air traffic, pilots are always taking over from one another as they proceed to the next stage in the process. As soon as an aircraft has landed, it is already being prepared for its next departure. But first, it has to be properly parked. The pilot receives precise instructions for taxiing and parking from the tower controller and ground personnel. On the way to the terminal, lighting systems help to find the exact position. The jet is then guided into its exact position by a parking system or guide.

After the engines have been switched off, the APU (Auxiliary Power Unit) at the rear takes over the power supply and air conditioning during transitional periods. If the aircraft is stationary for a longer period of time, the air conditioning and power supply are connected externally. A staircase or gangway gets installed to allow passengers to disembark. At the same time, the luggage is unloaded and the on-board catering is topped up or completely replaced. The aircraft is cleaned, the toilet tank emptied, the fresh water system refilled and, of course, kerosene refuelled.

Preparation for take-off

Extensive planning is needed before an aircraft can take off. The airline will pass this on to the pilots, who will check all the information and fine-tune it. The entire infrastructure and the technical condition are checked. This check is called “Pre-flight Check.” All important technical functions are examined, so to speak, under the magnifying glass.

During the so-called “Outside Check”, one of the pilots checks the external condition of the jet during an obligatory tour. Particular attention is paid to obvious damage, the condition of the turbines and control flaps, as well as the landing gear and brakes. The other pilot feeds the on-board computer with all imaginable data. Current weather information for the start will be provided live from the respective airport.

The pilot’s “Before-Taxi-Check” (check before the start of taxiing) is also necessary. The entire procedure is mandatory and must be carried out before each flight. Among other things, it is checked whether the doors are locked, all passengers are strapped in and the instruments provide correct information.

If necessary, the aircraft will then be cleared of snow and frost by the de-icing service during the cold season (see article Flying in winter). Which route is flown and whether departure restrictions exist is regulated by air traffic control units (ATC) and is stored in the navigation charts in the cockpit.

Ready for take-off: the wheels start rolling

Finally, it can start; the plane take-off begins. The engines howl up and the aircraft lifts slightly at the front. In most cases, the engine power is not fully utilized. In order to relieve the high-tech engines, the power peaks are reduced by a precisely calculated value. The existing track length should be used as efficiently as possible. This not only reduces the service life of the engines, but also other wear, noise and emissions.

In order to take off, a certain speed must already be reached on the runway, as this is the only way to overcome gravity so that the aircraft can take off. Commercial airliners accelerate to a proud 250 to 345 km/h.

The elevators cause the aircraft to rotate around its transverse axis. The nose of the aircraft is lifted and the nose gear lifts off. The point until which the pilot can abort the take-off is called V1. If he would take out the throttle until then, the glider would automatically perform a kind of “emergency braking”. After exceeding V1 the aircraft has to take off.

The tires of the airplanes are filled with nitrogen and only roll with it. This means that they are not driven by themselves, as in a car. The aerodynamic lift on the wings is achieved by increasing the angle of attack. First the nose wheel lifts off, then the rear wheels. The pull you can feel at this moment is caused by the gravitational force and is already over after a few seconds.

Finally the pilot takes off and retracts the landing gear. For 15 to 20 minutes the airplane is in the climb flight (Climb), before it changes into the cruise flight (Cruising).

A glimpse behind the scenes

In the following video you can see which commands the pilots exchange with the ground crew, the tower and also with each other during take-off and how the preparations for take-off proceed:

During the whole time, the passenger can sit back and enjoy the complete flight. The professionals on the ground, in the cabin, in the tower and of course in the cockpit take care of the rest.

Would you like to learn more about take-off from a technical and pilot’s point of view? This is what you will learn in this article.

Pictures Pixabay – Holgi, bernswaelz

by Paola Leibbrandt

Related Posts