[mcapodici]

Same with jet fuel on a plane. They calculate the amount to fuel carefully to be efficient but safe. Too much and the plane is heavier and uses more fuel. Too little and you might run out if put into a holding then diverted.

Obviously jet fuel is what it is it wont get more dense but a more efficient engine means less fuel needed means even more efficiency and so on.

[Swannie]

The Qantas 16h 45m flight from Dallas to Sydney aims for Brisbane, and then turns to Sydney as the plane approaches Australia. (10th longest commercial route in the world).

This allows the plane to land at Brisbane and refuel if the calculations are done wrong. Couldn't find stats on how many times it's had to land in BNE.

Pre-COVID, it was apparently common to try and off-load passengers to single stopover flights to reduce fuel needs (I was one of those passengers, and the crew confirmed it was a regular occurance).

[isolli]

It reminds me of this anecdote [0]:

An example is Singapore Airlines' former New York to Singapore flight, which could carry only 100 passengers (all business class) on the 10,300-mile (16,600 km) flight. According to an industry analyst, "It [was] pretty much a fuel tanker in the air."

[0] https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft

[crazygringo]

Knowing nothing about it, what causes fuel calculations to be done wrong?

Is it math errors, or uncertainty about exact weight of cargo and passengers, or wind conditions different from predicted, or something else?

[stenius]

Wind is the main one.

You might also run into some weather you didn't have to plan for and that changes the prevailing winds at the altitude you were previously cruising at or causes you to divert to fly around it.

[NovaDudely]

It was something I had never considered but it is wild to think about. I believe it was Vaclav Smil that highlighted it to me. On its longest trip an A380(I think?) takes off weighing 400 tons and lands weighing 200 tons. That kind of thing is just cool to ponder.

[arwhatever]

I realized while working on heavy transport aircraft that they their weight can be (very roughly) 1/3 aircraft, 1/3 fuel, and 1/3 cargo, and being struck by how different these proportions are from the family sedan.

[ryan93]

It is literally insane how much oil there is. Planes use i think less than 10% of world oil consumption.

[0xFF0123]

Rockets reaching orbit are an interesting example too.

[MaxMatti]

Not only that but too much might also cause you to have to dump fuel in order for the plane to be able to land.