[rhodozelia]

How much of the cost of a flight is fuel? What percentage of the mass being moved is passengers and their luggage be freight and the plane and fuel itself?

[JumpCrisscross]

> How much of the cost of a flight is fuel?

Better question: what fraction of airline's margins could one explain with the variation of passengers' weights? Airlines' pre-tax margins are low [1]. Almost any factor, meaningless or meaningful, will look tiny relative to revenues or costs.

[1] https://www.statista.com/statistics/225856/ebit-margin-of-co...

[ddeck]

>How much of the cost of a flight is fuel?

In terms of flight operating costs (FOC) per hour, about 16-36% according to the numbers for a 737-500 across for Continental/United/Southwest a few years ago.

It's very dependent on utilization. Fixed ownership (i.e. depreciation/leasing) costs start to dominate at low utilization rates.

Boeing 737‐500 FOC per block hour (~2017):

              Crew Fuel      Maint. Ownership Hrs/day
  Continental $510 $430(19%) $ 651  $698      3.9
  United      $927 $487(16%) $1048  $510      4.3
  Southwest   $388 $537(36%) $ 251  $350      8.2

https://www.icao.int/mid/documents/2017/aviation%20data%20an...

[WalterBright]

When I worked on the 757, it was 45%. The whole justification for the 757 was lower fuel burn due to a new wing design and new engines.

The same for the 737MAX.

[t0mas88]

Mid sized airliner roughly 90,000 lbs for the plane and equipment and 160 to 170,000 or so maximum take off weight depending on the variant. So a bit over half the weight is the plane itself the rest is fuel + people/freight.

[rhodozelia]

A 777-300 has a maximum take off weight of 660,000 lbs of which 312,000lbs can be fuel.

So an extra 100 lbs on every passenger is a drop in the bucket!

https://courses.washington.edu/ie337/Boeing%20Tour%20Facts.p...

[manwe150]

100 lbs * 500 passengers is 50k pounds or about 10% of the max takeoff weight quoted there. Those numbers seem likely to be over-estimates, but that seems not inconsequential?

Edit: the plane holds 328-550 depending on seat configuration per the above link. I went with the upper end of that range per consideration of the “safety considerations” indicating it is the upper end of that range that is being reconsidered.

[rhodozelia]

A 777-300 holds 388 passengers, so 39,000 lbs extra would be significant.

Is the average American 100 lbs heavier than the average person from the rest of the world? Probably nowhere near that.

[gield]

22 kg (48.6 lbs) according to [1].

[1] https://en.wikipedia.org/wiki/Human_body_weight

[t0mas88]

A 777 is not a mide sized airliner, wide body aircraft for long haul have very different calculations because their flight can easily be over 12 hours long.

The problem case for weight are the regional jets (E190 etc) and to a lesser degree the 737/A320 family. Those tend to be weight limited enough that you need to offload passengers or baggage if it's too warm outside.

[AceyMan]

fwiw, the old rule of thumb when I was trained is "it cost you one pound of fuel for every three that you carry", where 'cost' is in the form of increased burn (decreased efficiency).

Of course, fuel is no different than any other weight, so the same rule would apply to the revenue load (people, bags, freight)—for every three pounds it cost you one pound of fuel.

Incidentally, I've always felt ticketing should be pro-rata wrt weight. Well, where 'always' is defined as 'since I obtained my FAA dispatcher license.'

/Acey