Pilots like to fly as high as possible, because the air resistance is lower, the engines use less fuel and so it is cheaper. In addition, you often avoid bad weather.
However, if pilots fly too high, there is too little air to keep the engines running.Then they fall out. Most planes fly at the highest possible altitude that the engines can handle. There is of course a safety margin built in and there are other factors such as the weather, the flight plan, the weight and the air traffic situation that determine the altitude of a flight, but generally one tries to fly as high as possible.
Each airplane has a certified maximum height.The aeroplane must never fly higher than that altitude, except for some test flights.In practice, however, confusion has already happened that planes fly too high, and then the engines fall out as expected.
If the engines fail, the procedure is basically also relatively simple: bags to a lower height, and the engines reboot.The problem with a flameout or engine failure at that altitude and at low speed is that you can get the phenomenon ‘ core lock ‘ if the engines are not restarted immediately.Due to the engine failure and the low air velocity, the cooling air flow of the currently very hot motor is disrupted and different parts of the engine will cool in a different way, which will also distort them in a different way . This may mean that the parts of the engine do not actually fit together properly, so the engine is stuck and no longer can be started.
In many of these cases there was also a so-called tracing or stall (where the airplane loses force by the high angle in combination with the lower air pressure.This is an aerodynamic stall, which is distinguishable from a ‘ motorstall ‘. Restoring an aerodynamic stall is easy if it is recognized (which in some accidents has not always been caused by confusion): pushing the nose downward (which reduces the angle of incidence and increases the speed and air density and thus the Lift force increases).The most important thing with an aerodynamic stall or cover is that you have the space to do that. At high altitude This is not a problem.
In conclusion: If you fly too high, you can get both a cover and a motor outage.The first phenomenon is, certainly at that height, perfectly correct, provided it is correctly recognized. The second phenomenon is in principle also corrected, provided that a sufficiently high air velocity is maintained that prevents the ‘ core lock ‘ phenomenon.
An addition to Ben’s answer is that at higher altitude the stallspeed increases.Thus the speed at which there is no more enough lift over the wings is generated ever closer to the maximum allowable speed (Mmo = maximum operating Mach speed) of the appliance is located near until these speeds are equal.
This point is called Coffin Corner, in this point the airplane can actually nothing more: to slow down and the airplane loses lift and the pilot will lose control or fly faster and exceed the maximum speed, where the velocity of the airflow Also is large and there is flow separation, which also causes the aircraft to lose lift.
Both situations are not nice to sit in.In addition, steering in this point is to make no sense, because then one wing gets more speed than the other and both extremes are exceeded.
The ceiling of an airplane is the maximum height that it can achieve with maximum engine power.
When you go higher the airtightness will be lower.You have to fly faster to stay in the air or take a more stylish angle for your wing. That is closer to being overpulled. You need more engine power for that.
Also, your engine delivers less power because the air is less dense, so less oxygen per litre of engine content or continues.
That height, or air tightness, where your maximum engine power is equal to the power required to stay in the air, is your ceiling.
Everything you do there differently than fly straight out will make you descend.
Because the air tightness is also lower when it is Warmer, your ceiling will go down.
Mentour pilot had once published a good video about that.Here is ie: