Why does not start or stall the engine in the plane?

Due to the insufficient awareness of passengers about the operation of the aircraft systems, there are often unpleasant situations that lead not only to panic passengers, but also to the flight delay for several hours.

Most often these situations are associated with the operation of the engines. It happens that you sit on the plane, wait when the plane goes to his runway&# 8230; But for some reason, the engines do not start, or, even worse, it is harmful and almost immediately.

Usually among passengers in such situations, panic begins. After all, how to fly on a fault of the plane? But, by a minute, and you are sure that it is faulty? Crew members are the same people as you and they also have families, really, knowing the danger, will risk? Of course not!

If the plane engines did not start, there are no grounds for panic. To understand why this happens, let’s figure it out how the engine starts.

Airplane engine start air. In modern liners, in addition to the main, there is also a small engine, which is called the VSU (auxiliary power plant). USU is used to generate electricity, creating pressure in the hydraulic system and air conditioning during the location of the aircraft on Earth and the launch of the main engines. (VSU is needed only on Earth, it does not affect the flight)

From the auxiliary power plant to the main engines of the aircraft are the air ducts, when the air is started, the air supply is turned off from the air conditioning system and redirected to the main engines, this happens with the valve. The air, rushing to the main engine, starts to promote the turbine.

If the air pressure in the starting system is enough, then the turbine is spinning to the desired revolutions, follows the injection and a tag of a combustible mixture in the combustion chamber. Everything, the engine started.

But there may be a situation where pressure for some reason is simply not enough to promote the turbine. For example, a very high outdoor temperature, sand and t.D. Automation of protection in such situations will turn off the VSU and then there will be a breakdown. If the engines have failed from the second or third times, the Mobile Installation of the Air Start (UWS) approaches the aircraft.

And even she does not always have to start the engine from the first time (for example, if it stood without work a couple of weeks). If the engine still started, but then again stalled, then, most likely, the installation of the air launch did not spin the engine to the desired revolutions. This happens if it does not produce the required pressure or in the process of starting the pressure fell. In these cases, the engine is disabled to avoid overheating, and if after several attempts the launch was not performed, a pause is made (its duration depends on the number of attempts to start engines). And then everything starts first until the engines are launched.

As a rule, the installation of the air startup looks like this:

But at the our airports you will mostly meet UZZ based on UAZ:

Running the engine from installing air start not from the first attempt &# 8211; a regular phenomenon, as in general, the launch from UVZ, which does not interfere with the flight of the aircraft.

If in the plane on which you are going to fly, the engines do not go, do not panic, the call of UVZ costs money and considerable, so the airline sometimes want to save and try to start the engines on their own, it takes time. Yes, and UVZ comes not quickly, especially if you fly out of a major airport, where this device serves a lot of aircraft. In some cases it should be waiting for more than an hour.