TUI in takeoff-weight miss-take

[DWG]

Tui plane in ‘serious incident’ after every ‘Miss’ on board was assigned child’s weight

Service from Birmingham to Majorca took off with less thrust because pilot thought it was 1,200kg lighter

www.theguardian.com

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.

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.

 

[riggerrob]

This reminds us of the "Gimli Glider" an Air Canada flight that suffered fuel starvation. The problem was created by confusion over Imperial gallons, American gallons versus Metric litres in fuel calculations.

 

[Archibald]

... and that very unfortunate NASA Mars probe in 1999 which burned itself because some idiots had mixed metric and imperial units.

D'oh !

 

[DWG]

Both of which examples popped to mind when I was thinking about this. I did find a paper on some EASA research on passenger weight when googling around, which confirmed 69kg is in the right ball park for adult females (men came out at 82.6/86.3kg , women at 65.3/67.9kg and kids 2-12 at 31.1/30.7kg - figures are for summer and winter)

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

 

[Grey Havoc]

In Serious Incident, Software Glitch Miscalculates the Weight of Three UK Flights - Slashdot

A software mistake caused a flight on Tui airlines "to take off heavier than expected," according to The Guardian, citing an investigation by the UK's Air Accidents Investigation Branch An update to the airline's reservation system while its planes were grounded due to the coronavirus pandemic...

news.slashdot.org