Why does an airplane produce fuel. Why does an airplane run out of fuel before landing? The weight of the "iron bird"

Question A: I've always wondered why emergency landing planes don't dump fuel these days. Indeed, in a crash, many people can survive thanks to modern safety equipment on board the aircraft, but die in the fire that follows the crash or suffocate from carbon monoxide.

Answer: Do you think that pilots are aware of the inevitability of the crash and do not try to avoid it until the last second. This is not true. It is worth remembering that not all aircraft are equipped with an emergency fuel dump system.

Even if a crash occurs, a much smaller percentage of passengers die from burns or smoke than most publications claim. According to NTSB statistics, passengers who are involved in a major plane crash are much more likely to survive.

Question: What happens when a pilot dumps fuel? Does it dissipate and then evaporate? And where is it usually prescribed to do this, over land or over water?

Answer: Yes, if necessary, the fuel is discharged through a specially designed nozzle, which disperses it into tiny drops. The dumping of fuel itself is allowed only in specially designated places. To minimize the impact on residential areas, we must also not harm people on the ground.

Question: In the past, almost all aircraft models were equipped with an emergency fuel release system, but this system is usually not present in modern aircraft models. Why did engineers abandon this safety system and does it have worthy alternatives in modern aircraft?

Answer: Modern aircraft, unlike their predecessors, are equipped with an overweight emergency landing system, which gives pilots the opportunity not to make an emergency dump of excess fuel. After such a landing, the aircraft undergoes a thorough check to eliminate any problems that have arisen and to make sure that the aircraft is fully operational and ready to fly.

Each of us at least once in our lives used the services of airlines. They offer the safest and most comfortable mode of transport. In addition, with its help it is possible to significantly reduce travel time.

Surely many have seen a picture of how the plane circles for hours over landing strip and wondered: why is he doing this? After all, because of the extra hours of flight, a lot of jet fuel burns. This is exactly what a pilot is trying to achieve when he deliberately flies in circles without landing. He tries to burn as much fuel as possible. And about why the liner produces fuel before landing, we'll talk further.

The weight of the "iron bird"

During takeoff, as well as during landing, the mass of an airbus is extremely important. And in each case, it is calculated separately: for landing - landing, and for takeoff - takeoff.

The takeoff weight of the aircraft is calculated taking into account the total weight of passengers, their luggage, the liner itself and fuel.

At the same time, if the weight limit is exceeded, the aircraft will not be able to gain the required height or will not take off at all.

The landing mass of the "iron bird" is calculated in the same way. It also takes into account the total weight of the crew and passengers, the liner itself and the luggage on board.

Aircraft landing weight

There is a strictly limited weight of the aircraft coming in for landing. Under no circumstances should this limit be exceeded. this situation could cause an aircraft crash.

When landing, a kind of impact of the landing gear on the surface of the runway occurs. At the same time, the landing gear and fuselage are designed for specific loads, which directly depend on the weight of the aircraft. If this indicator is significantly exceeded, then the load will increase accordingly. The landing gear and fuselage may not withstand and break under the weight of the weight. Wings can also be damaged. That is why it is important to monitor the weight when landing.

Fuel dump

As a rule, the landing weight is slightly less than the takeoff. How is this possible, you ask? Everything is very simple. Any airbus is designed for the fact that during the flight most of the fuel from the tank will be used. Thus, when landing, it will weigh less than when taking off.

What to do in cases where the landing is made earlier than planned? The reason for this may be an emergency or a change in flight course. In this case, all the fuel will not be used up, because the path of the aircraft will be shortened. But landing with fuel in the tank is also dangerous.

In this case, some aircraft equipped with a special emergency fuel dump system can simply dump the fuel. If there is no such system, then the pilot has to circle over the runway, working out the remaining fuel. It will have to be spent even if conditions do not allow dumping this fuel.

Is it true that planes dump fuel before landing?

The most interesting thing is that today the planes practically do not dump fuel. Previously, aircraft had such a supply of fuel that was designed only for flight, in case of an unplanned landing, the aircraft either circled over the airfield to burn out the remaining fuel, or dumped it so that ignition did not occur during landing. Now progress has moved forward. Now a special powder is thrown into the fuel tank, which simply makes the fuel non-combustible and can not be dumped.

Today, such a phenomenon as fuel dumping is practically not found in the flight practice of pilots. civil aviation- and even vice versa - they are rewarded in every possible way for fuel economy - this is a business today and only in the event of an emergency will pilots dump fuel. If the fuel is constantly dumped, then the ecological catastrophe will be fast on Earth.

Airplanes do not jettison fuel before landing.

They have no reason to do this if everything goes according to plan and the landing is not emergency.

But if you need to land urgently, an emergency situation has arisen, then there are rules that air crews are forced to adhere to. Vehicle, and at which it is necessary to land the aircraft by dropping excess fuel.

Yes, this really happens in the event of an emergency landing. Once there was a rowdy passenger on board, whom the flight attendants could not calm down in any way. It threatened the safety of passengers and cabin crew. And the pilot decided to land the plane. The landing was made urgently at the nearest airport, but there was a lot of fuel left in the tanks. As a result, the pilots had to dump fuel. The brawler was arrested after the flight, and the airline sued him and collected a large amount of money. The same can happen with a sick passenger on board or an emergency on board where an emergency landing is necessary.

Fuel is dumped only during an emergency landing immediately after takeoff. Kerosene costs decent money, so no one will dump it unless absolutely necessary. A black mark usually does not occur during landing, but during takeoff, when the engine is running at maximum power in afterburner mode, a trace is left by soot from unburned kerosene residues.

An aircraft dumps fuel if it is forced to make an emergency landing, as there is a risk of an explosion. The more fuel left in the tanks, the stronger the explosion can be in case of failure. If the landing is unplanned, but not emergency, then the fuel is burned.

Here Sergey Rakitin quite rightly answered that the plane dumps fuel only in case forced landing, immediately after takeoff or somewhere in the middle of the way, but even then, if the situation allows, then kerosene not reset, and maximally produced to a safe weight. Emergency reset is done only in the case when the aircraft, for some emergency reasons, cannot fly in circles while running out of fuel.

Landing a plane with a lot of fuel on board is risky. The flight route and the refueling of the aircraft are calculated taking into account that there is enough fuel to reach the alternate airfield and that after landing at such an airfield there is still approximately one to three tons of kerosene left (this is for large liners).

In the event of an emergency fuel dump, behind the aircraft, not a black trace, but a white one, will be visible. The black trace is, as Sergei Rakitin writes, just soot and soot from kerosene.

Planes dump fuel only in the event of an emergency emergency landing to avoid fire. In some cases, if the situation permits, the crew continues flying on purpose in order to use up the maximum fuel supply. And no one dumps fuel on purpose.

During emergency landings, fuel dumping is necessary. And a reset is made only in the case when it is impossible to reduce the amount of fuel simply by producing it. Planes just fly in circles, running out of fuel. If this is not possible, then reset at high altitude.

By reducing the amount of fuel, the crew of the aircraft reduces the possibility of an explosion during an emergency landing and, accordingly, a fire.

When designing an aircraft (both civil and military, by the way) and in particular its landing gear, there is always such a parameter as the maximum landing weight. It is quite obvious that this is the maximum mass that the landing gear can withstand during landing.

When the aircraft is being prepared for a mission, it is filled with enough fuel to fly to the planned landing site + navigational fuel supply. When everything is normal, the fuel is not drained. If the crew decided to land the car, and its mass exceeds the maximum landing weight, then they get rid of the fuel. about to say that the aircraft burns fuel so that the load on the landing gear does not exceed the maximum load, otherwise the landing gear simply will not withstand.

Especially often such situations occur in the event of a serious failure immediately after takeoff. It should also be noted that not all aircraft simply “burn out” fuel in order to “lose weight”, some are equipped with an emergency fuel drain system.

Summarizing, we can say that the aircraft burns fuel so that the load on the landing gear during landing does not exceed the maximum, otherwise the landing gear simply will not withstand.

In the section on the question Why does an airplane need to burn all the fuel before landing? given by the author Irene the best answer is When designing an aircraft (both civil and military, by the way) and in particular its landing gear, there is always such a parameter as the maximum landing weight. It is quite obvious that this is the maximum mass that the landing gear can withstand during landing. When the aircraft is being prepared for a mission, it is filled with enough fuel to fly to the planned landing site + navigational fuel supply. When everything is normal, the fuel is not drained. If the crew decided to land the car, and its mass exceeds the maximum landing weight, then they get rid of the fuel. Especially often such situations occur in the event of a serious failure immediately after takeoff. It should also be noted that not all aircraft simply “burn out” fuel in order to “lose weight”, some are equipped with an emergency fuel drain system.
Summarizing, we can say that the aircraft burns fuel so that the load on the landing gear during landing does not exceed the maximum, otherwise the landing gear simply will not withstand.
Regarding the "breaking off of the wings" I can say the following: so what, and the wing of the aircraft, if something happens, will fall off last! To be convinced of this, it is enough to look (and I happened to count) on the moment attachment points of the wing with the fuselage. So don't worry about the roof!

Answer from Eurovision[guru]
Well, it's not always, only when there is some kind of breakdown. To prevent a fire and, as a result, an explosion.

Answer from wise[master]
not all of course. :) so that the plane can land. When an aircraft has a minimum amount of fuel during landing, it is easier for it to land ... All this is calculated in special programs ...

Answer from workable[guru]
During landing, there will be a confluence of electricity into the ground (since the plane is electrified in flight), and the fuel may explode.

Answer from Ask[guru]
the fuel has a lot of weight after takeoff, the tanks are in the wings. when landing with full tanks, various accidents are possible, such as breaking off the wings and damage to the tanks. and it is difficult for a heavy aircraft to land - more mileage along the runway, etc.

Answer from Oleg Orlov[guru]
The aircraft produces fuel only when EMERGENCY LANDING(rendered chassis, another failure) so that when emergency situation the fuel did not ignite. Remember Irkutsk (in my opinion), where the plane left for the take-off. He had fuel in his tanks that caught fire in the accident. And it was not worked out due to the fact that nothing foreshadowed an accident.

Answer from Bearing Blizzard "" [email protected]"" [newbie]
a plane with full tanks can take off!! but you won't be able to land! the wings are breaking!! when landing, the weight of the tanks + the force of gravity and free fall + acceleration are directed downwards, respectively, or the landing gear will not last or the wings will break off !!!

Answer from Lyokha[guru]
"Bearing the Blizzard", do not carry the blizzard. In a real emergency, the fuel is simply drained during the flight (I don’t know if this is possible on all planes. Probably not on all). IRKUTSK, etc., are out of business - for landing, braking, maneuvering, fuel is NEEDED. What remains for these needs is enough for a fire. Landing with a minimum supply of fuel is an additional security measure, BUT there is still quite a lot of it in the tanks, otherwise why would "planes circle for hours over the airfield" if the runway is occupied, the landing gear is not extended, the "glitch" of radar equipment, or you just had to fly to another airfield on weather conditions? I think Vitaly should get 10 points.