Gas Guzzling Airliners?

I recently stumbled on a website that preaches the evils of Gas Guzzling Airliners. The site’s curator is particularly agitated with Boeing’s new 747-8 and the Airbus A380. “These huge, four engine gas guzzlers are contributing to the demise of our planet!

dirty_jet
Retired 727. New jets are much cleaner!

Airplanes certainly add CO2 to the atmosphere, just like cars, trucks, power plants and other fossil fuel burning machines. But are airliners a wasteful use of fossil fuel? I thought it might be interesting to compare the fuel consumption of a car to that of an airliner. I had a hunch that airplanes aren’t as bad as this guy is making them out to be.

Apples To Apples

applesObviously, a small car burns considerably less fuel than a 500 passenger jetliner. We need to compare apples to apples by figuring out the fuel consumed per passenger for each mode of transportation. For my example, I’ll be using a family of three on a flight from Philadelphia to Los Angeles.

The AeroSavvy Barrister (not to be confused with the AeroSavvy Barista) wishes to inform you that my research consisted of a quick internet search. The data was not verified by any manufacturer or airline and wouldn’t survive the scrutiny of a high school term paper. Calculations were made on a wet, coffee stained Delta napkin covered with Biscoff crumbs while sitting in coach on a flight to Atlanta; so my high school algebra teacher won’t be impressed, either.

 

Liters / Seat / 100km

Manufactures often publish the fuel economy of their airplanes in the form of liters of fuel per seat per 100 kilometers (liters/seat/100km). This makes it easy to compare and play with the numbers.

Here are a few stats I found for three popular airliners:

 Airbus A380:  490 seats  2.9 liters/seat/100km
 Boeing 747-8:  330 seats  2.8 liters/seat/100km
 Boeing 737-800:  152 seats  2.9 liters/seat/100km

Notice that 2.9 liters/seat/100km seems to be a magic number? Airliners, big and small, are all pretty close in fuel consumption per seat (thanks to competition). Regional jets are a little bit higher (fewer passengers; thirsty engines).

Our journey from Philadelphia to Los Angeles is 3,865 km (2,400 miles) by air.
The same trip by car, according to Google Maps, is 2,735 miles.

Assuming all the seats on the airplane are filled (they often are these days), the fuel burned for each passenger on our flight is about 29 gallons. This works out to an impressive 82 mpg per person. Our family of three uses a total of 87 gallons or 27 mpg for the flight. I’m starting to feel a lot better about flying!

If our family of three drives the 2,735 miles to Los Angeles in a 2014 Subaru Forester AWD (28 mpg highway) they will burn at least 97 gallons of fuel. On this particular trip, our family saves the planet 10 gallons of fuel by flying.

fuel-panel
Fueling a 767

Turns out, large airplanes are similar to other mass transit vehicles like buses, trucks and trains. They burn lot of fuel, but because they carry a lot of passengers and freight, they become more economical than cars. Of course, there are fuel economy scenarios that don’t work out quite as well as my example. Shorter legs or flying two legs with a stop at the airline’s hub will work against the airplane’s good fuel economy numbers.

Even with added stops, if your travel group has three people or less, flying on an airline will usually use less fuel than driving a car – you’ll be saving gas and supporting your pilots!

Wait a minute, don’t you fly packages?

envelopes-2I sure do! Let’s see how much fuel is used to fly an 8 ounce overnight letter. A flight on a 767 from Seattle to Indianapolis takes 3 1/2 hours and burns about 4,700 gallons of fuel. If the payload (the stuff we carry for profit) is 70,000 pounds, the 8 oz letter requires about 0.033 gallons or only 4 ounces of jet fuel for the flight! Moving the letter by train, truck or ship will result in even better fuel economy, but it won’t be delivered overnight. Lucky for me, airplanes are FAST!

The best place to save energy?

greenhouseThe very best place to start saving fossil fuels is right at home. Turn down your thermostat in the winter, switch to LED bulbs, drive a fuel efficient car, join a carpool, and use mass transit when you can: Trains and Boats and Planes – and buses, too!

On that note, I leave you with Mr. Burt Bacharach…

2 Comments

  1. Hey Ken! Been reading on your site for about 30 minutes and already found answers to several longtime questions! Look forward to learning much more.
    Thanks and May God Bless You!

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