Questions tagged [fuel-systems]

Any question regarding aircraft fuel systems, how they work etc.

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0answers
126 views

Overheating (fire thrown out of the nozzle) [closed]

At first I copied https://www.jetcat.de/en/productdetails/produkte/jetcat/produkte/hobby/Engines/P160_rxi_b Where I manufactured and installed all the parts and they are very similar to the original ...
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0answers
59 views

When should the fuel pump be on in a Cessna 152? [duplicate]

I am a new student and just need help understanding the fuel pump system. For a Cessna 152, in which scenario would I have the fuel pump on ? Start ? After Start ? Before Take-Off ? After Take-Off ? ...
5
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1answer
856 views

How does a hot tip-jet supply fuel to its engines?

Some tip-jets move their rotors by running jet engines on each end of the rotor. Obviously there must be some ways to supply fuel to those engines through a rotating body. How is this accomplished?
9
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3answers
254 views

Why don't all cylinders have priming lines?

Questions about the primer for carburetor engines. Why does the primer only spray fuel to three (sometimes just one) of four cylinders. (Like Piper Cherokee or Seminole) And is it true that priming ...
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4answers
406 views

What are some symptoms of a clogged fuel filter?

I can certainly imagine one of the symptoms could potentially be engine fuel starvation. If the fuel flow to the engine isn't totally blocked, how can one recognize a clogged fuel filter?
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2answers
506 views

What is the difference between LP fuel valve and LP fuel shut off valve?

In the Airbus A320 FCOM in some places "LP fuel valve" is mentioned (in Fire and Fuel System chapters) whereas in the engine chapter "LP fuel Shut off valve" is mentioned. Is there ...
14
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2answers
2k views

Why nitrogen generation system is only present in centre tank only?

I was going through FCOM of A320 and it mentioned that nitrogen generation system is only there for centre tank and not for wing tanks what is the reason for the same?
2
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2answers
160 views

Is gascolator and fuel strainer the same thing?

I am wondering is gascolator the same as fuel strainer, or this two things are bit different. Because sometimes I see one term, sometimes another, and I don't know if I am reading about the same thing....
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0answers
61 views

What is a typical fuel temperature entering the burner for different mission flight points of a civil aircraft?

Is there a target regarding the fuel temperature that enters the turbine engine's combustion chamber and if so does it change with different operation flight points in civil aircraft applications? Is ...
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1answer
74 views

How long would the engine of a Tecnam P92 Eaglet run for with the fuel selectors turned off?

I'm wondering about a scenario where a P92 has been flying for at least 30 minutes or so, at say 4,000 RPM and 2,000' AGL at standard temperature (I'm not sure if these details matter). With both ...
0
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1answer
96 views

How do fuel tanks prevent free surface effect? [duplicate]

Free Surface Effect is a fancy term that refers to liquids changing their relative orientation within a container, whenever the container is rotated. So imagine a large plane banking very steeply, at ...
16
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4answers
7k views

Why do jet engine igniters require huge voltages?

Wikipedia's Components of Jet Engines has this to say on the igniters: A high voltage spark is used to ignite the gases. The voltage is stored up from a low voltage (usually 28 V DC) supply provided ...
17
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5answers
6k views

Why aren't “fuel polishing” systems removing water & ice from fuel in aircraft, like in cruising yachts?

Should you sump fuel tanks when the fuel system is below freezing? the question should one sump fuel-tanks before flying, if in freezing-conditions? but this implies another question that boggles me:...
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1answer
277 views

Why is “L Fuel Low” illuminating on my Cessna that is full of gas?

I fly a fuel injected Cessna 172SP 200 hp. Tanks were just about full today and every 5 seconds or so in flight, I would get “L fuel low” and the left fuel indicator would drop to 0. I’ve consulted ...
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1answer
132 views

How much pressure do boost and jettison fuel pumps produce?

What is the pressure output of a (boost) fuel pump on a Boeing 767 and/or 777, compared to a heavy-duty jettison fuel pump.
17
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1answer
2k views

How does the fuel pump work in a PA-28 and when should I use it?

Just started flying again after 14 years and I'm taking this to the finish line this time. All my time, up till 10 am today, is in a C172. I did fly a PA 28-151 today and liked it. I do have some ...
3
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3answers
200 views

Where does fuel from the boost pumps go before engine start?

For example let’s take the PT6A-27. In every video related to engine start I see, the fuel boost pump is turned on, and then the fuel pressure goes up. Example: My ...
8
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2answers
455 views

How can the fuel decrease evenly from both wing tanks when an A320 is running on APU only?

I stumbled over this sentence in a training material about fuel leak: "If the fuel quantity symmetrically decrease in both wing tanks and the fuel quantity in the center tank decrease, the fuel leak ...
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0answers
130 views

May an A330 depart with with empty outer fuel tanks?

Airbus does not recommend flying with empty outer tanks, to reduce stress on the wings. Also, when the outer tank transfer valve is inoperative, the MEL says to fill the outer tanks with fuel and it ...
5
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1answer
588 views

How much unusable fuel is in the A320?

I was wondering how much unusable fuel is in each tank or maybe in total for an A320. I searched through the FCOM and could not find answers. To add to this question is the fuel shown on the fuel SD ...
9
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1answer
169 views

How is the fuel quality monitored/assured for jetliners?

With tens of thousands of flights daily, many out of smaller and perhaps 'sketchy' airports, it would seem that serious incidents caused by contaminated fuel should happen a lot more often (in a quick ...
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2answers
2k views

Why does pulling the mixture to idle cutoff increase the RPM slightly?

When adjusting fuel control on a reciprocating engine, why is there a slight RPM rise (50-RPM rise) when pulling the mixture control to idle cutoff? Why if more than a 50-RPM rise, carburetor is set ...
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1answer
336 views

How to find the remaining fuel without electrical power on the MD-80?

After a flight, how to find the remaining fuel without electrical power (even the APU) on the MD-80?
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1answer
172 views

What is the difference between staged and unstaged fuel manifolds? [closed]

Also, I would like to know the difference between pilot, primary and secondary fuel flow.
3
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1answer
333 views

Is fuel in trim tank usable?

Some aircraft (A380, Concorde,...) are equipped with a trim tank in the tail. Transferring fuel from or to this tank help controlling the CG. This feature can only be achieved if there is fuel to ...
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1answer
444 views

What is the difference between fuel control unit and fuel flow meter (transmitter)?

Hello can someone explain the difference between the fcu and fuel flow transmitter and how they work together alongside the fuel pump?
5
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3answers
875 views

What causes fuel gauges to be untrustworthy?

I went on my first flight yesterday (Cessna 152), and I was told not to trust the fuel gauges and to check fuel levels manually. The instructor said that the only fuel gauge reading that I can trust ...
15
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4answers
8k views

What is the purpose of the fuel shutoff valve?

Most GA planes have a fuel shutoff valve which I don't quite understand the purpose of. Does it cut the fuel flow with the mixture. My theory is to prevent fuel flow at earlier stage for safety ...
2
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0answers
181 views

Are there design guidelines for sizing vent/surge tanks?

Could someone explain the sizing process of Vent/ Surge tank of Aircraft fuel system? I understand the Vent tank is to collect fuel overflow from the main fuel tanks. The reason could be due to Fuel ...
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0answers
143 views

Airbus a380 fuel system [duplicate]

Does the aibus a380 has center tank compare with a320,in this picture above,it shows that it has 11 tanks including the wings and the elevator while many aircraftshas together with the center tank (i ...
7
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1answer
810 views

Does the mixture and throttle setting affect the quality of priming of fuel prior to start?

This question is a generality. For airplanes with small reciprocating engines, does the mixture and throttle setting at the time of priming affect the quality of the priming or the engine start, or ...
2
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1answer
2k views

How do you lean mixture using only the instruments on a C172 Skyhawk?

POH manuals always tells to use the voice of the engine as a reference. (Which complicates things a little bit since carbs and fuel injected planes have different "reaction times" for each cylinder) ...
8
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1answer
357 views

Why was the Graf Zeppelin's endurance when fully fuelled with both fuels less than the sum of its endurances with each fuel separately?

The LZ-127 Graf Zeppelin used a unique dual-fuel system, with both a gasoline tank and a set of gas cells filled with blau gas; the airship could be flown using either fuel or both. The purpose of ...
0
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1answer
171 views

Why doesn't the Convair 580 have check valves to prevent inadvertent fuel transfer?

The Convair 580's fuel system is composed of two wing-mounted fuel tanks (one in each wing), each with its own shutoff valve (which can be closed to isolate its respective tank from the rest of the ...
2
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2answers
3k views

Why is the fuel pump in the startup procedure for a Cessna 172?

I thought fuel pumps were reserved for fuel injected planes in startups and during critical flight phases for all planes? However. There are some X-Plane flight tutorials that tells us to use fuel ...
7
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5answers
1k views

Why is alcoholic gasoline such a showstopper for aviation?

One of the main reasons the common avgas grades are still full of 3-plumba-3,3-diethylpentane is the incompatibility of many aircraft fuel systems with the oxygenates (primarily ethanol, with some ...
10
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1answer
2k views

Why would the outer tanks fuel on the A320 be colder than the inner tanks?

I have noticed in a number of instances during long flights typically over 5 hours the fuel in the outer tanks on the A320 are colder than the fuel in the inner tanks. This goes against the system ...
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2answers
346 views

Why are fuel pump switches separate?

Since engines are run only when the fuel pumps are on and vice versa , why are there separate switches for this? Why can't it be automated ?
4
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1answer
1k views

In normal condition, is the Airbus A320 APU fuel supplied by the main engine boost pump only?

I have a question relating to APU fuel system. As said in material, there are 2 system supplying fuel for APU to operate. 1st one is primary and 2nd one is secondary. In the 1st system or low ...
12
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2answers
3k views

Why fuel left/right when C172 is secured?

The C172 POH checklists say to set the fuel selector to "right" or "left" when securing the plane but "both" while operating the plane. What is the point of changing the fuel selector when the engine ...
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1answer
2k views

Hydromechanical/Electronic fuel control system [closed]

Can someone explain the picture below which represents hydromechanical/electronic fuel control? What's the function of the solenoid on the picture below? What are the differences between solely ...
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5answers
19k views

Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?

In the approach phase, engine 1 of Cathay Pacific flight 780 got stuck at about 70% N1 and it forced the crew to do an overspeed landing (230knots). Why didn't they shut it off by turning the fuel ...
3
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0answers
94 views

Could injectors be used as an alternative to turbopumps in jet engines?

Could injectors be used instead of turbopumps in aeroengines? Are there jet engimes that already use them? https://en.m.wikipedia.org/wiki/Injector
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1answer
133 views

What's this fuel line for?

Cessna 414 ram conversion What's this fuel line for that is coming to injector , other then the one from fuel disturbutor ?
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9answers
37k views

Why are fuel tanks located in wings?

Passenger aircraft have fuel tanks in the wings. Why? What are the advantages and disadvantages of this location ? examples of disadvantages I would suspect: added weight increases the structural ...
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2answers
4k views

Why does the cabin air sometimes smell of kerosene? [duplicate]

Why does the cabin air sometimes smell of jet fuel, although bleed air is tapped before it comes in contact with fuel ? How is this possible? I have smelled this a couple of times in my life (twice ...
4
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1answer
830 views

Why do the A320's centre tank pumps stop working 5 minutes after the low level has been reached?

I'm new here and I'm in training course for Airbus A320. In the training material, it's said that the centre tank pumps are controlled to stop automatically 5 mins after the low level fuel has been ...
1
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1answer
729 views

Does preheating fuel before it reaches the turbine result in a performance improvement?

Preheating fuel before it reaches the combustion stage was first proposed several decades ago as a way to improve mixture, fuel economy, and to reduce emissions in car engines. One example of this ...
85
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5answers
20k views

Why do we need to starve the engine before turning it off?

This question is for Piper Tomahawk, but I guess applies to any small aircraft. Why do we need to use the fuel mixture to starve the engine before turning it off with the key? Why can't we just turn ...
3
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3answers
3k views

Are there any 100% renewable energy aircraft in development?

There seem to be several options for aircraft R&D regarding cleaner fuels for the time when fossil fuels are no longer economically viable. Some of these include: Algae. A drop-in fuel. These ...