Questions tagged [fuel-systems]

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

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7
votes
1answer
1k views

Why not leave an electric fuel pump on all the time?

This question is related to single-engined piston airplanes equipped with an electric fuel pump like the Piper Dakota/Arrow etc. The POH states that the fuel pump should be switched on for takeoffs/...
3
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2answers
2k views

Was there ever a fuel-injected Spitfire?

I couldn't find one but did it ever exist? Would adding fuel injection have improved combat effectiveness or fuel efficiency?
2
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1answer
73 views

Are there any Part 135 (On-Demand Passenger Charter) companies out there that use Aviation Bio-Fuel?

I was recently approached by a client asking if I can provide charters on environmentally conscious aircraft that run on Aviation Bio-Fuel. Anyone have any insight on what is required for an ...
6
votes
1answer
326 views

Where is fuel metered in continuous flow fuel injection system?

How is fuel metered in continuous flow fuel injection system?
1
vote
1answer
814 views

Does an increase in inlet temperature affect fuel flow and power output?

The fuel flow rate decreases as the inlet temperature of the air entering the engine increases. Will the engine produce same amount of power as when the fuel flow was higher?
23
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2answers
7k views

Why are the center tank pumps deactivated when slats are extended on the A320?

Why are the center tank pumps deactivated when slats are extended on the A320? I researched about this and all I can see is hints. They say it is because of regulations or certifications.
2
votes
1answer
196 views

Is there a use scenario for the Detote value?

Im currently working on the fuel calculation of an airplane, when i stumbled upon a value called "Detote". When asking around, no one knew what the use case of this value is or why it even exists. In ...
40
votes
6answers
11k views

Is fuel moved around during flight on a passenger or cargo plane? If so why?

Is fuel moved around during flight on a passenger or cargo plane? If so why? Is balance an issue?
1
vote
1answer
138 views

Would fuel quantity indications be affected by extended flight at nonzero bank angles?

If flying with a 20kt crosswind requiring yaw input as well as roll input to maintain course, would the fuel indicators show different loads depending on the roll angle of the aircraft (in this case, ...
71
votes
6answers
23k views

Why are fuel tanks in the wings filled first, and why are they used last?

When fueling airliners, why is fuel filled first in the tanks in the wings and then the center tanks? And why do they use fuel from the center tanks first and then from the tanks in the wings? From ...
3
votes
2answers
411 views

How are fuel tanks tested and certified?

What ground tests are carried out for testing and certifying wing fuel tanks for use in passenger aircraft? Is there any chamber to simulate flight conditions? If so, how is the chamber constructed?
9
votes
4answers
2k views

How do you know which fuel an aircraft uses?

Other than the decals on the plane, how would you know what fuel to use in an aircraft? Where is this limitation documented? For some aircraft, does this limitation include some sort of substitute ...
4
votes
0answers
195 views

Is there an indication in the cockpit when the refueling control panel door is open on the ATR72?

Is there any indication (light, MFD/SD displays) in the cockpit of opened/closed refueling control panel door in ATR72-600?
16
votes
3answers
8k views

Is excess fuel leaking normal during take off of a B737?

When we look over this video it's noted that some fuel is coming off from the left wing during the rotate. This is the position of the fuel vent within the wing, ...
1
vote
1answer
792 views

Why does an aircraft use less fuel while landing as opposed to takeoff and climb?

I read that the weight ratio of an aircraft after and before landing, was larger than the ratio after and before takeoff. The weight is lost only due to fuel burn, so why does an aircraft appear to ...
15
votes
3answers
2k views

What is the appropriate fuel tank selection to land a 172?

On a recent checkout on a C172 I was told to select "fullest tank" as opposed to "both" that I have been doing for years. Given the aircraft is high wing (gravity feed) with no auxiliary fuel pump ...
10
votes
1answer
522 views

What are possible explanations for fuel being expelled in this video?

In another question, I asked about whether or not a fuel spill would be reportable or not. The answer was "no", because the aircraft was not in flight. What are the possible causes of the spill ...
4
votes
2answers
686 views

Do Diesel engines have a mixture option?

Consider the DA-42, it has no mixture control. Is that because it is run on Jet-A/diesel? Or is the mixture control automated?
2
votes
1answer
310 views

Do glow plugs face fouling?

Do glow plugs face fouling? I understand that spark plugs foul on occasion, do glow plugs face the same issue?
7
votes
1answer
519 views

Can you safely operate a 777 with diesel?

Is it possible to safely operate a Boeing 777 on diesel instead of Jet-A? Are there any regulations that prevent this? Would it cause any damage?
3
votes
1answer
372 views

What are the dimensions of an NPT pipe for fuel systems?

I have a question about NPT (National Pipe Thread) tapered connectors that are used in fuel systems of several airplanes. Please take a look at this standard-wall one-side threaded nipple (3/4 pipe ...
7
votes
1answer
2k views

What is the freezing point of 100LL Avgas?

Does anyone knows the exact freezing point of Avgas (100LL) ? I found that Jet A-1 freezes at −47 °C / −53 °F (wikipedia), but didn't manage to find any info on Avgas.
3
votes
1answer
313 views

What is the relationship between fuel mixture and RPM in a reciprocating engine?

I'm doing a project on a safety occurrence but I don't understand how the RPM of an engine is affected by the fuel mixture. How does a richer than normal mixture result in lower RPMs?
1
vote
3answers
2k views

What is a fuel tank float valve and how does it work?

This report on dodbuzz mentions a 'fuel tank float valve'. Neither google nor StackExchange seem to know what it is. What is it, why is it necessary?
5
votes
1answer
2k views

Where is the fuel vent on a Piper Archer TX?

I realized I haven't really noticed where the fuel vent is for the 2016 Piper Archer TX that I've flown, but I assume the fuel is vented from the fuel cap. Is that correct?
12
votes
5answers
6k views

Why is mixture lean recommended on the ground?

Mixture lean is typically recommended during the ground operations at sea-level pressure in the POHs of most small aircraft equipped with a carburetor system. Why is it? I heard some people saying it'...
5
votes
2answers
3k views

Why does fuel vaporization in a carburetor cause a temperature decrease rather than a rise?

So I know the most "prominent" conditions of carburetor icing is anywhere from 20 to 70 °F with visible moisture. There is also a tendency to have icing in the carburetor in the venturi throat due to ...
3
votes
1answer
1k views

How does this fuel pump work?

This question is about the fuel pump controlled by the hydro-mechanical fuel control unit. This is part of a fuel system for a turboprop engine, described on this page which actually comes from a ...
2
votes
1answer
886 views

Why are ambient pressure and burner can pressure always the inputs on a hydromechanical fuel controlling system?

I worked on several of these older systems using a hydromechanical fuel control. I've noticed that the inputs at the fuel control are for the most part the same. Power lever angle, N2(N1 on a single ...
11
votes
1answer
394 views

How do fuel trim and air bubbles prevention work in inverted flight?

I was reading Why do many GA aircraft not have a "Both" fuel selector? and voretaq7's excellent answer got me to thinking. He cites the regulations noting that the plane must only draw fuel from one ...
48
votes
2answers
7k views

Why do many GA aircraft not have a “Both” fuel selector?

I've been trying to rack my brain around this and asked a few CFI's who couldn't give me more than "because that is how it was done", but a good number of GA aircraft save for Cessna and maybe a few ...
3
votes
1answer
561 views

What happens to the control systems of a BAe 146 when the aircraft runs out of fuel?

On a BAe 146, is there any way to control the aircraft when it's out of fuel? Does the APU run on a separate tank? Can the engines be windmilled for power generation?
0
votes
1answer
262 views

How does an aircraft distribute fuel equally between powering the turbines on the engine and injecting it into the afterburner?

How does an aircraft distribute its fuel equally between powering the engine turbines and injecting it into the afterburner?
-1
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2answers
1k views

Where does the fuel that the mid-air refueling probe collects go to?

Where does the fuel that a mid-air refueling probe collects go to? Does it go straight to the engine, to the fuel injector(s), or does it go to some place that then sends the fuel somewhere?
18
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2answers
1k views

How is fuel managed in the Zero-G A310?

There are several Zero-G airplanes to experiment briefly microgravity without going into orbit. One is the A310 from Novespace (F-WNOV): Novespace A310 F-WNOV (source: Jonas Wirz at Airplane-Pictures....
16
votes
1answer
4k views

Why is fuel used as a hydraulic fluid?

Why is fuel used in some servo-systems as a hydraulic fluid (fueldraulic systems) of modern civil and military aircraft such as the Boeing 777-200/-300 (Pratt & Whitney PW4084) or the Lockheed ...
8
votes
1answer
309 views

Can IPA be used as a FSII with MoGas, particularly with a Peterson STC?

This question established a basis for the use of 100% Isopropyl Alcohol (IPA) as a Fuel System Icing Inhibitor (FSII) in aviation gasoline systems. However, this Cessna Service Letter documents that ...

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