Hacker News new | past | comments | ask | show | jobs | submit login

AFAICT, this NOTAM system is a nationwide bulletin-board, using some cryptic standard abbreviations (to save space as if they were paying 1990s SMS), usually filtered by locale/coordinates/path, so pilots have the latest news hat might affect their flight plans.

Has anyone seen exactly how many NOTAM messages are generated per day, and how long of a look-back is required?

From 50k feet, it looks like something that could be replaced with a cryptographically-authenticated massively-replicated virtual data structure that's oblivious about, and robust against all sorts of failure in, the exact systems, languages, update-paths, etc used to keep it in sync or implement any one user's view.

All that pilots need to know is: "I have a full local copy, signed by the right update-authorities, as of roughly-now."

From a glance, NOTAM's uptime this year looks worse than Ethereum, but a bit better than Solana or Binance Smart Chain.




This is highly informative. No seriously, it's probably the best thing I've read on NOTAMs.

https://deathtonotams.com/

from there you can get to

https://fixingnotams.org/

and pilots won't stop laughing and crying when they read

https://fixingnotams.org/wp-content/uploads/2019/11/Field-Gu...


And the answer to the question, "How many?"

About 1.5 million per year.


Thanks! It looks like individual messages are rarely more than one, under-80-character line long.

So we're talking, (1.5M * 80 bytes=) 120MB a year, uncompressed. (With the tiny controlled-vocabulary, maybe 6x compression possible?)

Every pilot could have a RAM-resident local queryable copy in a their commodity handheld devices.


This is great stuff, thanks! Can't shake the feeling a tiny team of professional modern software/system designers, paired with some aerospace old hands, could create a far-better (but also backward-compatible) system in short order.


> using some cryptic standard abbreviations (to save space as if they were paying 1990s SMS)

When I did my initial pilot training in the late 1980’s, the codes for METAR, TAF, and NOTAM had already long been in place. It was explained to me at the time that the encoding was a practice that dated back to its origins in the teletype era. I suppose the limited baud rate of these devices meant that economizing on symbol density was a good idea. I’d still much rather read these succinct formats because it’s easier to chunk it at a glance.


The abbreviations way pre-date SMS - they were standardised back in the teletype days, 1940s-1950s, when printing speed was 30-100cps! Now NOTAMs (mostly) comply with global standards so, like VHF AM aviation radio, substantial changes are impractical.

There is significant debate concerning the number (too many) and size (too long) of NOTAMs, but I can assure you that when you get an unexpected rerouting on a dark, bumpy, busy night, you do not want to be reading pages on plain-text prose! All experienced pilots are comfortable with the cryptic NOTAMs, and are used to scanning the abbreviations for important items :)


> cryptographically-authenticated massively-replicated virtual data structure that's oblivious about, and robust against all sorts of failure in, the exact systems, languages, update-paths, etc used to keep it in sync or implement any one user's view. All that pilots need to know is: "I have a full local copy, signed by the right update-authorities, as of roughly-now."

You've solved one problem and created several more problems.


Crypto-authenticated update & replication works really, really well nowadays. Lots of open-source support, extensive testing, proven track records even in adversarial deployments.

Especially for a simple log-like system, with a limited number of permissioned authorities.


cryptic abbreviations in the NOTAM system reminds me of telcos using CLLI codes for unique geographical locations of physical telecom infrastructure sites - a legacy of 1960s mainframe stuff where the number of characters in a database field for text entry was extremely constrained.

https://en.wikipedia.org/wiki/CLLI_code




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: