Re: Bad Data Input/High System Utilisation.
> aviation likes semi-formatted telex-style messaging for some reason though
"some reason" is to do with the requirement for global accessibility ! There is also the issue of making things easily comprehensible.
So messages are text only - while it may be true that few places (if any) in the world now cannot get access to modern comms like "the internet", that certainly wasn't the case when the standards were laid down. Back then, Telex was the norm - which itself imposes some of the restrictions (see below - no lower case !)
And just like every other industry, you want the information to be easily and quickly understood - so a set of standard abbreviations which are compact and quick to read. Eg, from the weather reports/forecasts we get things like PROB30 instead of "there's a 30% probability" and loads of other things that make it quick and compact. For example, take a current (as I write) forecast :
TAF EGCC 231700Z 2318/2424 22014KT 9999 SCT020 TEMPO 2318/2322 24016G26KT TEMPO 2318/2402 4000 RADZ BKN012 BECMG 2323/2402 28012KT TEMPO 2323/2402 BKN009 PROB30 TEMPO 2412/2418 29015G25KT=
Longhand, the weather forecast at Manchester, produced at 5pm Zulu time (or British winter time if you prefer) on 23rd is : validity between 6pm on the 23rd and midnight on the 24th; wind will be from 220˚ at 14 knots, visibility over 10 kilometres, scattered cloud at 2000 feet. Temporarily between 6pm on the 23rd and 10pm on the 23rd expect wind from 240˚ at 16 knots and gusting to 26 knots. Temporarily between 6pm on the 23rd and 2am on the 24th, visibility will be 4000 metres with rain and drizzle, and broken cloud at 1200 feet. Between 11pm on 23rd and 2am on 24th wind will become 12 knots from 280˚. For periods between 11pm on 23rd and 2am on 24th could will be broken at 900 feet. And there's a 30% probability that between mid-day on 24th and 6pm on 24th the wind will be 15 knots from 290˚ with gusts to 25 knots. Ends.
So the "code" version is around 1/4 of the space of the longhand version - which matters when you have a pages with many reports on it. Also, because it's a standard code, it's much less open to interpretation (and particularly, misinterpretation) than freeform text. If you don't allow freeform text (ie restrict to a standard set of terms) then it makes little difference in terms of what you need to learn whether the code is verbose or terse (as long as the terse code isn't also "opaque") - but it makes a big difference to speed of transmission, the space it takes on paperwork (and screens), and so on - in the past (I know some will find this hard to believe, but there was a time before "ubiquitous" mobile internet !) I've used text-back services to get weather forecasts and the terse code is a lot easier to read on a small mobile screen. The above would overflow onto two texts, but most forecasts would fit within the 160 character limit of a single text.
To anyone for whom the above information matters, reading it takes seconds and leaves no room for misinterpretation.
Yes, things could probably change - but this means the whole of the world changing. Getting global agreement (via ICAO) for a change is a very very slooooooooooow process ! No country/region/group of countries can go it alone and change without the others doing so. Sticking with this example, the above forecast would have come from the UK Met Office - but is distributed internationally. The weather at Manchester is not just of interest to people in the north of England - but to operators/pilots of all flights flying into Manchester from anywhere in the world.