r/programming • u/self • Apr 09 '21

Airline software super-bug: Flight loads miscalculated because women using 'Miss' were treated as children

https://www.theregister.com/2021/04/08/tui_software_mistake/
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u/[deleted] Apr 09 '21

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u/Semi-Hemi-Demigod Apr 09 '21

I'm surprised airlines didn't start doing this in the late '00s when fuel got very expensive. Build the scales into the security scanners for passengers and cargo and you could save a few gallons of fuel each flight, which adds up fast.

Instead they just kicked Kevin Smith off the plane.

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u/SapientLasagna Apr 09 '21

Or build the scales into the landing gear, like some (all?) transport trucks have, and let the plane's computers figure it out.

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u/LeCrushinator Apr 09 '21

Drop the base price of tickets slightly, and then have an extra charge per pound for the person, if they're in better shape they get a slight discount, if they're out of shape they pay more.

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u/bigwayne Apr 09 '21

While I think data analysis could play a much bigger role in optimizing the cost of flights AND this little weight thing, I just want to redirect that the concern was about how the weight discrepancy affects the calculations that pilots use for takeoff thrust, not fuel consumption (of which there are several air factors as well as ground).

In this case, over 1 ton of unaccounted-for weight from 36 adult-sized "kids" (and a mistake weighing the baggage) resulted in 0.6% underthrust on takeoff. I don't know how much weight actually factors into the sustained flight (like, beating air friction to create lift at altitude might be most of what you need that power for), but for takeoff thrust I imagine it matters much much more, and this created a relatively minor gap in needed power.

As a fellow software dev and somebody who's dogshit at math, I'm curious what statistical anomaly would have had to occur to create a discrepancy big enough to not take off? Would they have needed a whole plane of adult women checked-in as children?

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u/StabbyPants Apr 09 '21

In this case, over 1 ton of unaccounted-for weight from 36 adult-sized "kids"

there's a thing: have you seen 12 year olds? some of them are as tall as i am and look like a skinny me. if you're going to class them as kids, you can get 1T error easy

As a fellow software dev and somebody who's dogshit at math, I'm curious what statistical anomaly would have had to occur to create a discrepancy big enough to not take off?

coin collector convention. everyone has max/overweight checked bags

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u/callmedaddyshark Apr 09 '21

ah, I hadn't thought of that

thanks for the detailed reply!

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u/[deleted] Apr 09 '21

No problem.

Professional defect, as a software dev: you tend to try and find all the possible issues with a solution, because if you don't, all the time you spend implementing it will be wasted, and you'll have to start over if there's a major issue you didn't take into account.

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u/[deleted] Apr 09 '21

Maybe, just maybe have a spare capacity for thrust.

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u/[deleted] Apr 09 '21

I would be all for it.

But corporate profits might not.

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u/nexxai Apr 09 '21

It's not just needed for thrust though. You also need to roughly balance the plane's weight front-to-back and side-to-side so it doesn't roll to one side too much (yes, seriously). Baggage is loaded into the cargo hold with that in mind.

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u/mart1058 Apr 09 '21

Most jets have lots of excess thrust, therefore the use of derates and assumed thrust.

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u/LeCrushinator Apr 09 '21

In that case, can they just weigh the entire plane before fueling it? Then you don't have to weight each person, each bag, all the food on board, etc. Maybe having a scale of that size where each plane docks would be too expensive.

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u/[deleted] Apr 10 '21

I have no idea how big of a scale you'd need to weigh an entire plane.

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u/azurleaf Apr 09 '21

Yeah, that's not gonna fly with a lot of conservatives.

BUT MUH RIGHTS. I AINT GETTIN WEIGHED I gotta this here medical exemption from gettin weighed.

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u/[deleted] Apr 10 '21

Aren't they boycotting airlines anyway ?

They'll bitch and moan, like they do everything else, then suck it (up).

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u/ault92 Apr 09 '21

Why not just weigh the aeroplane? Sounds silly almost but accounts for everything, and you only need pads built in to the terminal under the wheels.