Takeoff-weight Miss-take

[davidgillon]

www.theguardian.com/world/2021/apr/09/tui-plane-serious-incident-every-miss-on-board-child-weight-birmingham-majorca

TLDR: Apparently TUI had updated their reservation software during the first lockdown - with everything grounded - and it allocated everyone on the flight using 'Miss' as their title a child's weight at 35kg vs an adult weight of 69kg. Which meant 38 adults were rated as children and the pilot's take-off weight and thrust calculations were 1.2 tonnes light.

The UK uses 'Miss' as a female title for both adults and children (as well as both 'Ms' and 'Mrs' as alternate adult titles), while apparently the country the software change was offshored to only used 'Miss' for female children. Which just shows how careful you need to be both writing and reading specifications to be sure all assumptions are clear and you aren't running into some sort of international discontinuity.

At least it wasn't Metric vs Imperial this time! (Yes, that has happened).

Comments

[alexseanchai]

I weigh distinctly more than 69kg and I am the smallest person in this household, so like, I feel there was more than one wrong assumption here

like, before we even get into how many under-18s are adult-sized (which is a substantial fraction of high schoolers, and a larger fraction if we define "adult-sized" by statistics for over-18s instead of by the eventual full growth of the high schoolers in question)

[davidgillon]

It's all an approximation, and should average out, and in most cases being a little off will just mean you take a bit longer to takeoff and burn a bit more fuel en route. EASA (European Air Safety Agency) did some checking in 2009 and got an average female weight of 65.3kg in summer and 67.9kg in winter over a sample of 4,500 female passengers. As that research splits data into male, female, and 2-12, I'm presuming teens are counted as adults. (For completeness, men came out at 82.6/86.3kg and kids at 31.1/30.7kg)

https://www.easa.europa.eu/sites/default/files/dfu/Weight%20Survey%20R20090095%20Final.pdf