Earlier quoted context omitted.
[flagged]
The question isn't really how many would think it meant nanonmeters, it's how many would recognise it as nautical miles.
In aviation? Literally everyone. Context clues should make it obvious.
Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
51–60 of 311 posts
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#52[deleted]
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#53Good news: the system successfully detected an error and didn't send bad data to air traffic controllers. Bad News: the system can't recover from an error in an individual flight plan, bringing the whole system down with it (along with the backup system since it was running the same code).
> he system can't recover from an error in an individual flight plan, bringing the whole system down with it From the system's POV maybe this is the right way to resolve the problem. Could masking the failure by obscuring this flight's waypoint problem have resulted in a potentially conflicting flight not being tracked among other flights? If so, maybe it's truly urgent enough to bring down the system and force the h…
Yes I agree. The reason the system crashed from what I understand wasn't because of the duplicate code, it was because it had the plane time travelling, which suggests very serious corruption.
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#54Earlier quoted context omitted.
Sorry no. One interpretation, especially on this site, is that the problem was some kind of database bug, maybe where the same location was entered twice and a tiny location error ended up creating two locations. I expect that out of any random sample 500 million literate and mentally healthy English speakers, more than 450 million of them are totally unaccustomed to thinking about nautical miles ever. Even people in…
[flagged]
I assumed the post title meant nanometers. Why? Floating-point rounding bugs. A nanometer is about 9e-15 degrees of latitude, which is right about where a double-precision floating point number runs out of digits. So, if a piece of software uses exact `==` equality, it could easily have a bug where two positions 3600 nanometers apart are seen as being different, even though they should be treated as the same.
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#55Earlier quoted context omitted.
[flagged]
The question isn't really how many would think it meant nanonmeters, it's how many would recognise it as nautical miles.
I used to work on military boats combat systems. I scanned the title, read it nanometers, thought it was weird, mentally corrected to nautical miles being familiar with the context and cursed the person who wrote the title for the incorrect capitalisation.
So, yes, people who have worked in a related field get it. Still annoying though.
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#56Earlier quoted context omitted.
Or even more straightforward, just don’t believe anyone 100% knows what they are doing until they exhaustively list every assumption they are making.
Which also means never assume the exhaustive list is 100%.
Bingo, without some means of credible verification, then assume it’s incomplete.
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#57Earlier quoted context omitted.
Or even more straightforward, just don’t believe anyone 100% knows what they are doing until they exhaustively list every assumption they are making.
Which also means never assume the exhaustive list is 100%.
I wouldn't be able to produce such a list, even for areas where I totally do know everything that would be on the list.
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#58FYI: nm = nautical miles, not nanometers.
[flagged]
I too first read it as nanometers. Perhaps it's just those with engineering/science backgrounds who have far more experience with nanometers than nautical miles?
I've never had cause to see the abbreviated form of nautical miles, but I know nanometers. Also, given purely the title I could see it being some kind of data collision due to precision errors between to locations that should be the same airport but perhaps two different sensors.
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#59When there's no global clearing house for those identifiers, maybe namespaces would help? Related: The editorialized HN title uses nanometers (nm) when they possibly mean nautical miles (nmi). What would a flight control system make of that?
The reason idents for radio navaids (VOR/NDB) are only three characters is because they are broadcast via morse code. They need to be copyable by pilots who are otherwise somewhat busy and not particularly proficient in Morse. For this purpose, they only need to be unique to that frequency within plausible radio range.
'nm' and 'NM' are the accepted abbreviations for nautical miles in the aviation industry, whether official or not.
Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code
#60Earlier quoted context omitted.
The question isn't really how many would think it meant nanonmeters, it's how many would recognise it as nautical miles.
In aviation? Literally everyone. Context clues should make it obvious.
> In aviation? Literally everyone. Context clues should make it obvious.
But this is Hacker News, not Aviation News, and there are plenty of people, like me, who might find this interesting but aren't in aviation. I also thought it meant nanometers.