51 votes
Accepted

Why is the 777 fuel burn rate graph U shaped and skewed to the left?

What does the graph show? The graph plots the average fuel required per distance as a function of the total flight distance. It does not show fuel flow rate as a function of time during the flight. ...
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  • 44k
29 votes

What is more environmentally friendly? An A320 or a car?

I'm going to simplify and assume that jets and cars burn the same fuel, and output the same exhaust, CO2, NOx and all. I'm going to compare only short-haul flights against cars. According to ...
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  • 10.8k
27 votes

Why cruise at 7000' in an A319?

The only reason for your flight to operate at such low altitude is because it is cheaper for them to do so. As you said it is due to weather, other route/altitude may not be available. They can ...
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  • 7,940
24 votes
Accepted

What is the most 'environmentally friendly' way to learn to fly?

Here are some options for flying in an environmentally friendly way: Use an electric trainer: Since last year the all electric trainer aircraft Pipistrel Alpha Electro has FAA certification. Assuming ...
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  • 44k
19 votes

Has there been any attempt to use an underground cable system, a la a cable car, to tow aircraft along taxiways?

Way to go on thinking outside of the box. Actually, it might work. Although the logistics of it are above my pay-grade. Maybe, some smart group out there could make it work. But, your question doesn’t ...
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  • 16.1k
18 votes

Can the plane Celera 500L be eight times more fuel efficient than a jet of similar size and capacity?

tl;dr: L/D of the airframe and specific fuel consumption of the engines are credible but that doesn't add up to the claims made regarding fuel consumption and speed relative to jets. Laminar flow ...
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16 votes
Accepted

Why cruise at 7000' in an A319?

It was because they could get there faster on a "TEC route." IFR flights are subject to congestion management at the ARTCC level, which means they have to wait their turn in line to be allowed into ...
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  • 25.1k
15 votes

What is the most 'environmentally friendly' way to learn to fly?

By using as much simulator time as possible.
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  • 17.2k
13 votes

What is more environmentally friendly? An A320 or a car?

It depends on what you mean by "environmentally friendly." Just for an example, let's consider a 1000 mile trip. An A320 burns about 5 gallons of fuel per seat per hour, and with 150 seats this comes ...
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  • 69.7k
11 votes
Accepted

What is more environmentally friendly? An A320 or a car?

Overall, the two very different methods of transportation have surprisingly similar amounts of emissions, so close it's tempting to oversimplify things to a statement like "planes are 20% more ...
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  • 6,325
11 votes

Has there been any attempt to use an underground cable system, a la a cable car, to tow aircraft along taxiways?

Practically this would not work due to the sheer size of the cable you would need. A fully loaded A380 is 1.25 million pounds. A B787 is .5 million pounds and a B737 is about 150,000 pounds. On a busy ...
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  • 49.1k
11 votes

Would an airliner climb higher late in the flight because of the consumed fuel (lighter airplane) to save more fuel?

There are a number of variables that influence a decision whether or not to climb to a higher altitude as fuel is burned and the airplane becomes lighter. Burning less fuel, as you note in your ...
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  • 17.1k
10 votes

How much fuel is used for the different phases of the flight of a typical airliner?

From this site by Boeing for the B737-800: fuel used for TO and climb = 2,300 kg. From this site: fuel burn in cruise for B737-800 is 2,500 kg/hr From this site: fuel burn at idle of a CFM56 engine = ...
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  • 57.7k
10 votes

What is the typical fuel consumption of a 737 in MPG?

The following table shows the long range cruise control data for a Boeing 737-800 (source: FCOMv1 Performance Inflight - All Engine PI.31.2): Let us consider a typical cruise at FL370 with a weight ...
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  • 44k
9 votes

What is more environmentally friendly? An A320 or a car?

While not specific to an A320, nor a make/model of automobile, these averages may help put your question into perspective. How any of it relates to "environmentally friendly" is purely subjective. "....
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9 votes

How much does it cost extra to fly with one additional passenger?

I am basing the following calculations on the excellent answer by Peter Kämpf to this question: How much of an improvement would a 1% weight decrease on an airplane be to the industry?. We can ...
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  • 44k
8 votes

What is the most 'environmentally friendly' way to learn to fly?

Learnt to fly a solar powered hot air balloon The UK's International Balloon Fiesta in Bristol is a celebration of all things hot air ballooning, but this year it's taken a big stride into the ...
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8 votes

Does burning fuel to get to your max landing weight violate any regulations?

This scenario isn't common but it isn't exactly rare, either. You take off with a full plane & lots of fuel for holding & an alternate, planning to arrive just at max landing weight. Then, due ...
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  • 41.8k
8 votes
Accepted

Why is my calculated seat-miles per gallon of small aircraft higher than of big aircraft?

All else being equal, your intuition is correct that a larger aircraft will be more efficient (in a gallons per seat-mile measure) than a smaller aircraft. That's why there are big aircraft like 747'...
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  • 41.8k
7 votes
Accepted

Can longer paths consume less fuel than the (shorter) great circle path?

On a flat plane, the shortest distance between any two points is a straight line, right? So if you were at A and wanted to get to B in as few steps as possible, you would walk a straight line. But ...
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  • 1,123
7 votes
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Is it possible for a plane to be over fueled (and over-weight) to take off?

The aircraft you flew on was D-AIUX, a Lufthansa Airbus A320-214. On 10 February it was scheduled to fly from Munich to London, but the flight was cancelled due to the storm: (flightradar24.com) If ...
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  • 44k
7 votes
Accepted

What are the engine-out implications of giant turbofans?

Both-engine-out glide performance isn't accounted for and isn't a certification requirement (of any airplane that I'm aware of). Airliners have good glide performance as a happy side effect of design ...
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  • 104k
7 votes

Does endurance include the fuel reserve time?

Endurance is the length of time the aircraft will fly for a given set of conditions. There is no reserve fuel built into aircraft or their designs, because there's no constant definition of reserve. ...
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  • 8,840
6 votes
Accepted

What is the 'fuel cost' of a pneumatic braking system vs. a hydraulic one, in terms of weight?

There is an existing triple redundant hydraulic system in those planes required used for the control surfaces. Those are not something you want controlled by pneumatics. This means the weight of the ...
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