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Questions tagged [fuel]

Different aircraft engines use different fuels; the most common types are Jet A or A-1 for jet and turboprop engines, and avgas for piston engines.

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Why does the F-111 sometimes squirt a giant fire plume behind it? (NOT afterburners!)

As seen in multiple pictures: First, this one, it appears the aircraft is spraying copious amounts of fuel into the exhaust! Surely this provides no thrust, not in the way an afterburner (which the ...
Bassinator's user avatar
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71 votes
6 answers
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Why do jet engines use kerosene rather than gasoline?

Could you run a jet with gasoline? Why do all jet engines use kerosene?
yippy_yay's user avatar
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60 votes
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11k views

Why would a fighter drop fuel into a drone? [closed]

According to the BBC: A feed from a camera fitted under the fuselage of the surveillance drone shows a Russian SU-27 making two extremely close passes while releasing, what appears to be, fuel as it ...
Elerium115's user avatar
46 votes
5 answers
19k views

Why are we still putting lead in our fuel?

Lead in gasoline for automobiles has been banned from nearly every corner of the world, with most bans dating from the nineties. Why are we still poisoning ourselves with lead in Avgas? I understand ...
falstro's user avatar
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45 votes
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Why is water-contaminated fuel bad, but water-injection is not?

A "wet" takeoff of a KC-135 with J57 engines—By USAF Photographer (USAF photo) [Public domain], via Wikimedia Commons Why is water-contaminated fuel bad, but water-injection is not? The way I ...
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43 votes
1 answer
4k views

How can an altimetry system error during cruise (500 ft at 35000 ft high) cause an insufficient fuel situation?

So my boss gave me a question today as my daily quiz: Let's say an A321 is cruising on a 6-hour flight. It reaches FL350 30 minutes after take-off. After another 8 minutes there's a discrepancy ...
Light Le's user avatar
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41 votes
6 answers
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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?
Sarah's user avatar
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40 votes
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What are the differences between fuel types (comparing with vehicles)?

I find it funny that at gas stations, generally you can purchase "regular" gasoline (in various octane levels) or diesel. At airports, generally you can purchase 100LL avgas or Jet-A. Can you compare ...
digitgopher's user avatar
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39 votes
3 answers
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How do aircraft keep fuel from freezing while in flight?

On aircraft which fly above 30,000 feet, the temperature can often can get to temperatures below Jet-A's freezing point. For example: at 36,000 feet the standard outside air temperature is -56.5°C (-...
Qantas 94 Heavy's user avatar
38 votes
2 answers
15k views

Why is jet fuel cheaper than piston fuel?

Why is Jet-A cheaper than 100LL? Shouldn't it be the other way around?
TayE's user avatar
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35 votes
2 answers
96k views

Which engine is more efficient between turboprop vs jet?

Are turboprops really more efficient than jets? If yes, does that mean that airlines who use jets sacrifice fuel for faster flights?
Taher Elhouderi's user avatar
30 votes
3 answers
12k views

Where does Air Force One refuel?

Obama came to Greece and then to Germany. That's a long trip, even for the majestic Jumbo. There was a lot of discussion about where the aircraft was refuelled during that trip. Do we know, in general,...
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What makes a smokeless jet engine?

I was recently reading about the MiG-29 and its many upgrades, one of which (MiG-29M) was to smokeless engines. What makes a smokeless jet engine? Is it just the fuel, or something about the way the ...
DrZ214's user avatar
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30 votes
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6k views

What features enable the Su-25 Frogfoot to operate with such a wide variety of fuels?

It is widely attested* that the Su-25 Frogfoot's engines (the Turmansky R-95Sh and later the R-195) were designed to function using a wide variety of fuels, including diesel, gasoline, petrol, ...
Party Ark's user avatar
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29 votes
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Why don't we see business jets with wingtip fuel tanks anymore?

There is something I miss from the Learjet 35 (one from FS95/98) that I don't see any more: Fuel tanks on the wingtips! What happened to the wingtip integrated fuel tanks in the business jet industry?
Delta Oscar Uniform's user avatar
28 votes
2 answers
3k views

Was this flight a fuel emergency?

Yesterday I flew from San Diego to Boston in a commercial 737 operated by Alaska Airlines. Before landing we spent almost an hour circling. When we finally landed, many passengers were surprised to ...
Thomas's user avatar
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28 votes
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What are the ICAO fuel reserve requirements?

How much reserve fuel are private and commercial aircraft required to carry by ICAO rules? I heard that it changed recently (about a year ago) and is a little complicated. How is it calculated for ...
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27 votes
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Is it cheaper to drop cargo than to land it?

Is it more fuel efficient to drop cargo onto a runway from the air en route to a final destination than to land and unload it using a more fuel efficient plane?
Muze's user avatar
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27 votes
3 answers
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Why are piston engines for aircraft rarely diesel powered?

Why hasn't diesel caught on much for aircraft engines? The list of diesel aircraft engines on Wikipedia is very short. The reason I see mentioned is their poorer power-to-weight ratios. (e.g. What ...
curious_cat's user avatar
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27 votes
1 answer
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What exactly is an FBO and what services are provided?

To most non-U.S. pilots who have little or no experience flying in the U.S., the concept of a FBO is not very well understood. What exactly is a FBO and what are the services that it can provide? I'...
Philippe Leybaert's user avatar
26 votes
5 answers
5k views

Why is fuel usage discussed per time, not per distance?

I don't understand why sometimes the fuel used for a flight is discussed in terms of fuel used per time. I think I have seen it a couple of times here - not sure whether it was in some common context. ...
Volker Siegel's user avatar
25 votes
7 answers
12k views

Could most commercial jet engines today run on ethanol without any problems?

Most commercial jet engines today would be those large jet engines on large passenger craft like a Boeing 747. Can these run on straight ethanol without any problems? Would more maintenance be ...
DrZ214's user avatar
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24 votes
11 answers
13k views

Why do piston engines in aircraft burn fuel at a higher rate than a comparable car engine?

I've never understood why piston powered plane engines burn such a large amount of fuel per time period than car engines. Can anyone elaborate on this? I know that a C172M will burn ~5-9+ gph at ...
N Klosterman's user avatar
24 votes
4 answers
10k views

What happens if you do emergency landing on a US base in middle of the ocean?

A theoretical situation. I fly from Honolulu International to the Bejing but my private jet gets fuel starvation and then I land on the Wake Island airstrip. What happens next? Would the military ...
Delta Oscar Uniform's user avatar
23 votes
2 answers
5k views

What happens to incoming flights when the airport shuts down?

In Die Hard 2 terrorists take over an airport's ILS and landing lights on a snowy night (visual landing is impossible) and start making threats essentially holding the planes hostage. The tower ...
ratchet freak's user avatar
21 votes
6 answers
44k views

Why is water in the fuel tank bad?

I mean, on the one hand it seems kind of obvious, if you had a fuel tank that was mostly water then you would lack combustible materials for the engine, but I get the impression that having any water ...
Jae Carr's user avatar
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21 votes
4 answers
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Are commercial pilots incentivized to reduce fuel consumption?

Commercial airlines spend a lot of their operating income on fuel, so in order to maximize shareholder value presumably like to use as little fuel as is safely possible. Are commercial pilots ever ...
Digital Trauma's user avatar
19 votes
4 answers
10k views

Did any Boeing 787 operator achieve the 20% fuel efficiency improvement over the 767?

Is there any airline which are able to get the complete 20% fuel efficiency on their 787 with respect to 767 it is going to replace, as told by Boeing. I have read that one of the early customer like ...
NitinG's user avatar
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19 votes
3 answers
17k views

Why is AVGAS so much more expensive than car gas?

Why is 100LL so much more expensive than gasoline for cars? I get the fact that it's 100LL, instead of 87, 91, etc. For example (as of now, 13 Oct 14), the 91 unleaded gas at my local gas station is ...
Keegan's user avatar
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19 votes
3 answers
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How fast can fuel be siphoned out if you leave the cap off?

It is a dreaded scenario; forgetting to secure the fuel cap. I understand the low pressure area generated above the wing will siphon fuel out of wing tanks, how fast would this happen in a smaller GA ...
falstro's user avatar
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19 votes
4 answers
10k views

What should I do with fuel drained from the sumps during preflighting?

What should one do when done sumping a small amount of fuel during a pre-flight? Should it be dumped on the ramp? Or is it considered necessary to find the container far away from the airplane? Is it ...
EpicDewd's user avatar
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18 votes
3 answers
8k views

How much water is produced in jet exhaust?

If a jet has typical combustion efficiency, what equivilent amount of liquid water will be created per gallon of jet or kerosene fuel. An acceptable answer can be a ratio in weight or volume to the ...
jwzumwalt's user avatar
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18 votes
4 answers
6k views

Do I have to declare an emergency if I cut into fuel reserves?

In another question, I wrote You only need to plan for regulatory reserves. You don't actually have to land with them and @Jan replied: you have to declare emergency if you do cut into them though ...
rbp's user avatar
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18 votes
2 answers
2k views

How do pilots detect fuel contamination in flight?

According to the Aviation Herald, an Alitalia Airbus A330-200 diverted en route "reporting fuel contamination". How can the pilots detect fuel contamination in flight?
Tim Landscheidt's user avatar
18 votes
2 answers
68k views

What is the history of "Joker" and "Bingo" fuel terms?

Why do we use, in military aircraft, the words "Joker" and "Bingo" to indicate the fuel status of the aircraft? What is the history of these two terms?
Carlo Nava's user avatar
18 votes
2 answers
2k views

What is the cost savings of using electronic motors to taxi?

Aircraft manufacturers are now planning to use High Torque electric motors on the nose wheel of the aircraft, which is powered from the APU, to taxi the aircraft from the gate to the runway without ...
Victor Juliet's user avatar
17 votes
4 answers
8k views

Where I can get historical jet fuels prices?

I would like to analyze jet fuels prices in 2014. Where can I get jet fuel prices for 2014, only in USA and Russia? As there are different types of fuels, it would be okay to get prices for one (...
LA_'s user avatar
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17 votes
1 answer
6k 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 ...
user avatar
16 votes
2 answers
6k views

How is engine fuel kept from freezing? [duplicate]

The following table shows the operating temperature of Jet fuels (Source http://www.skybrary.aero/) I know a lot of flights will be cancelled during bad weather conditions including the cold. How is ...
Lucky's user avatar
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16 votes
2 answers
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Does the APU consume a lot of fuel compared to a jet engine?

I would like to know whether the APU of modern commercial airliners consumes more or less fuel than a jet engine. Of course, this will vary between aircraft types, so what comparisons in fuel usage ...
Manu H's user avatar
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15 votes
3 answers
12k views

What are the concerns and consequences of an overweight landing?

If a 777 ER has to immediately land after takeoff on a planned 14,594 km trip (in the case of a fire, e.g.), the landing will be executed with a very heavy aircraft. What are the major concerns of ...
Jonas G. Drange's user avatar
15 votes
2 answers
3k views

Under what conditions are passengers required to take precautionary measures during refueling?

I was on a recent flight with a fuel emergency, during which the passengers were required to take precautionary measures. Under what circumstances are the precautionary measures mentioned below ...
dotancohen's user avatar
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15 votes
3 answers
6k views

Why shouldn't you use HF radio while refueling?

FCOM limitations for many aircraft state: DO NOT USE HF RADIO WHILE REFUELING Why is this? I have heard from people that it's because most of the big airliners have a 'notch' antenna for HF; it's ...
Praveen Pillai's user avatar
14 votes
6 answers
7k views

Has anyone burned hydrogen in a gas turbine?

I am just wondering if supplying compressed hydrogen to a gas turbine (combustor) would be a better fuel as it has three times the octane rating of kerosene. It just seems better all around.
Skyhawg's user avatar
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14 votes
3 answers
6k views

Can a commercial airliner be too heavy to take off?

According to this question's answers, MTOW (or MTOM) is the Maximum Take Off Weight, which is everything up to and including trip fuel. Then there is one step above that, MRW, or Maximum Ramp Weight, ...
CGCampbell's user avatar
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14 votes
1 answer
2k views

How is fuel stored and routed on a trijet with one engine at the tail?

This question pertains to trijets with two engines on the wings and one at the tail, like the Lockheed Tristar. It does not pertain to trijets with all engines at the tail, like the Tu-154. (And it ...
DrZ214's user avatar
  • 17.8k
13 votes
6 answers
17k views

Do airplanes dump fuel before landing?

Presumably planes aren't completely empty of fuel when the land, so they don't start refueling from zero, is that right? Is it true that they must dump excess fuel before they land? How much? ...
Pat's user avatar
  • 369
13 votes
1 answer
1k views

Why might a passenger jet fly at altitudes in a strong headwind when the winds are more favorable at a different altitude?

I was a passenger on an east to west flight recently. During the flight I was playing with Garmin Pilot's new "Flight profile" feature that nicely shows the wind speeds at various altitudes, and I ...
Greg Taylor's user avatar
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12 votes
2 answers
3k views

How does new media streaming technology equate to fuel cost increase?

In regards to this article on BBC, which discusses the use of streaming technology to allow passengers to watch films/TV shows etc. on their portable devices, the following statement caught my eye: ...
Phizzy's user avatar
  • 401
12 votes
2 answers
4k views

Why is dual crossfeeding prohibited on DA42?

Diamond 42 AFM says: The fuel crossfeed function can be tested simultaneously with both engines. Proper function can be tested by running the engines for approx. 30 seconds with CROSSFEED ...
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