# How much of my airfare pays for fuel?

Samoa Airlines is in the news for a new pricing scheme that charges customers by the pound. It looks like a simple linear scale, i.e. a 300-pound passenger will pay twice as much as a 150-pound passenger.

Which seem silly. More weight on board certainly requires more fuel, but not twice as much, and I expect a substantial portion of a passenger’s airfare goes to pay for labor costs, airport costs, and equipment costs, which don’t substantially change with a passenger’s weight.

I suppose maintenance costs might go up a bit if the plane regularly hauls more weight, but I would guess the biggest increase in cost would be for fuel.

so that’s my big question. In my \$300 airfare between Detroit and Colorado, how much of that is paying for fuel for the flight (assuming an aircraft with all passenger seats occupied by adults weighing, on average, 175 pounds)?

From another perspective, this makes sense. Don’t think about fuel costs per passenger. Instead, consider that sometimes putting a person in every seat can exceed the takeoff weight limits for a plane – IIRC this can happen during certain runway or weather conditions, or perhaps for the very long range flights from Samoa. Say the plane has 200 seats, but can only take on 30,000 lbs of passengers. If everyone weighs 150 lbs on average, they can fill every seat. But if one passenger weighs 300 lbs, even if they fit in one seat, the airline has to leave an additional seat empty to keep the weight down.

It’s tricky to work out because airfares aren’t really set based on the cost of any particular flight. Some amount of fuel is necessary to fly the plane with just the pilot on board no matter what the weight, and the weight of luggage is a sizable factor as well, not to mention the weight of the fuel itself which may be more than needed for any particular flight.

Despite all that, I don’t think it’s unreasonable to make total weight of passenger and luggage a factor in passenger fares, that’s the way freight is charged.

People weigh more than before; airlines may use obsolescent weight averages; weighing passengers at check-in would be rude; so fatal accidents have resulted from passenger weight under-estimates.

On further research: Samoa Air has exactly three aircraft; a pair of 3-seat Cessna 172s and a 9-seat BN-2 Islander. I don’t think we have to conjure up edge case hypotheticals of overweight 737s in unusual flying conditions to understand why they might be interested in passenger weight.

FWIW, pricing is rarely logical. The point is to squeeze as much money out of the customer as possible, and provide any rational-sounding excuse you can. For instance the cost difference(to the company) between the cheapest thing on a Starbucks menu and the most expensive thing is something like 25 cents; the difference to the customer is something like 3 to 4 dollars. So, Samoa Air has said let’s see if we can squeeze some more money out of someone; this sounds like something the customer might fall for.

Anyway, according to Fortune, in 2010 fuel represented \$97.85 of a average \$506.62 flight from NY to LA, so that was about 19% then.

Googling around, I get that the average cost of fuel is about \$3/gallon, and 3 gallons are used per mile on a 737. For a 2000 mile flight is 6000 gallons or \$18,000. If there are 200 passengers that’s about \$90 per passenger. So… concur.

Of course that’s back of the envelope and doesn’t take into account a myriad of variables, but still.

Interesting that it’s a Samoan airline doing this, as Samoans are among the most overweight people in the world – over 90% of residents of both Samoa and American Samoa are overweight.

I guess there won’t be any outcry of minority discrimination in this case.

This only makes sense for very small airlines. For any major or even medium size carrier, they have so much changing overhead the idea that your ticket is specifically paying for the fuel, maintenance, crew’s salary etc. of your individual plane is simply not the case.

BTW, they did this way, way back when airlines first started. There’s olde timey footage of each passenger stepping onto a large scale before boarding. All flight attendants originally had to be RNs too…

I read a book by a pilot a few years back (a rather snarky one in which he was pissed that flying had changed and people were getting on his planes in jeans) in which he recounts a takeoff that seemed to take miles more runway than expected. They finally groaned off the ground and got airborne. He found out later that most of the passengers were headed to a coin collecting convention and had 200 pounds of luggage each.

:dubious:

Suspicious story is suspicious.

IANAP, but I thought the total weight of the aircraft was known before pushback from the gate. They have to assume a weight for the passengers and their carry-on luggage, but checked luggage all gets weighed. Doesn’t that info get reported to the cockpit crew for calculating takeoff roll and fuel requirements?

And I understand a lot of people might be going to one particular city for a coin convention, but why would a whole bunch of them be coming from one city, on one particular plane?

Agreed. If the story didn’t conclude with the pilot saying he turned the plane around and landed back at the same airport, it’s almost certainly bogus.

The amount of fuel on board is calculated for the needs of the flight. If the plane was so overloaded that it noticeably affected the takeoff but the pilot hadn’t been informed of this extra weight, he’d make the assumption that the airline probably hadn’t told the fueling crew either and the plane probably didn’t have enough fuel on board to complete the flight.

Perhaps it is rude, but it once happened to me. In London, on a prop plane, in 1964. All passengers were weighed along with all their carry-on. In those days, you were limited to 44 lb of checked luggage and it was always all weighed. After all that, we then flew to Glasgow to refuel (how close is that to London?) and then non-stop to NY. If it were done as a matter of course, people would get used to it. If commercial space flights ever happen, you can expect they will weigh passengers.

It all depends on what size aeroplane we are talking about. You do burn more fuel in a heavier aircraft but it might only be a matter of a couple of percent difference. It is also not uncommon to tanker fuel, ie take more than required.

The story is the least suspicious if the aeroplane is relatively small and it’s a charter flight specifically to carry the coin convention passengers. All it takes then is for nobody to bother weighing the bags. In a reputable company that wouldn’t happen, but some dodgy general aviation company could well take shortcuts like that. Also in a small aeroplane, being overweight for take off would have no great effect on the fuel burn.