271–280 of 459 posts
What I don’t understand in situations like this when thousands of flights are cancelled is how do they catch up? It always seems like flights are at max capacity at all times, at least when I fly. If they cancel 1,000 flights in one day, how do they absorb that extra volume and get everyone where they need to be? Surely a lot of people have their plans permanently cancelled?
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My jaw kept dropping with each new bullet point.
Same, is aviation technology really this primitive?
https://sfstandard.com/2023/02/02/sfs-market-street-subway-r...
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Yes but shouldn’t one step of the code be to translate these non-unique human-readable identifiers into completely unique machine-readable identifiers?
How exactly would you do that? It’s impossible to map from a dataset of non-unique identifiers to unique identifiers without additional data and heuristics. The mapping is ambiguous by definition. The underlying flight plan standard were all created in an era of low memory machines, and when humans were expected to directly interpret data exactly as the programs represented it internally (because serialisation and de…
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Why on earth do they not have GUIDs for these navigation points if the names are not globally unique and inter-region routes are commonplace?
What three words would be a better solution than a guid, as transmittable over radio.
Aviation already uses phonetically pronounceable waypoint names. Typically 5 characters long for RNAV (GPS) waypoints, for example "ALTAM" or "COLLI". Easy to pronounce, easy to spell phonetically if needed, and easy to enter.
The problem is the list of waypoints are independently defined by each country, so duplicates are possible between countries.
Rather than replacing a system that mostly works (and mandating changes to aircraft navigation systems, ATC systems, and human training for marginal benefit)... an easier fix would just be to have ICAO mandate that these waypoints are globally unique.
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What three words would be a better solution than a guid, as transmittable over radio.
W3W contains homonyms and words that are easily confused by non-native english speakers. Often within just a few KM. The latter is why ATC uses "niner", to avoid confusing "nine" and "nein". Talk to someone deep in the GIS rabbit hole and you'll get a rant about how bad W3W is: https://cybergibbons.com/security-2/why-what3words-is-not-su...
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> an EXACT SAME system took over and ran the exact same code Did you ever work with HA systems? Because this is how they work. It's two copies of the same system intended for the cases when eg. hardware fails, or network partitioning happens etc.
No, I do not. But HA systems work like that because hardware or network failure is what they are designed to guard against, not a latent bug in the software logic. If there's a software bug, both systems will exhibit the same behavior, so HA fails there.
* Live + standby. Typically, the state of the live system is passively replicasted to the standby, where standby is meant to take over if it doesn't hear from the live one / the live one sends nonsense. (For example, you can use Kubernetes API server in this capacity).
* Consensus systems where each actor plays the same role, while there's an "elected" master which deals with synchronization of the system state. (For example, you can use Etcd).
In either case, it's the same program, but with a somewhat different state.
It doesn't make sense to make different programs to deal with this problem because you will have double the amount of bugs for no practical gains. It's a lot more likely that two different programs will fail to communicate to each other than one program communicating to its own replica. Also, if you believe you were right the first time: why would you make the other one different? You will definitely want to choose the better of the two and have copies of that than have a better and a worse work together...
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Yes. It would cascade into: Changes in how ATCs operate Changes in how pilots operate Changes in how airplanes receive these instructions (including the flight software itself, safety systems, etc.) Changes in how airplanes are tested Changes in how pilots are trained Etc. In this case, the refactoring requires changes to hardware, software, training, manufacturing, and humans.
Pretty sure that is still not the meaning of refactoring. As I understand it refactoring should mean no changes to the external interface but changes to how it is implemented internally.
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Why on earth do they not have GUIDs for these navigation points if the names are not globally unique and inter-region routes are commonplace?
1. Pilots occasionally have to fat finger them into ruggedized I/O devices and read them off to ATC over radios. 2. These are defined by the various regional aviation authorities. The US FAA will define one list, (and they'll be unique in the US) the EU will have one, (EASA?) etc. The AA965 crash (1995-12-20) was due to an aliased waypoint name. Colombia had two waypoints with the same name within 150 nautical miles…
you're saying what-3-words (W3W) is unsuitable for safety critical applications ? /s
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Yes but shouldn’t one step of the code be to translate these non-unique human-readable identifiers into completely unique machine-readable identifiers?
How exactly would you do that? It’s impossible to map from a dataset of non-unique identifiers to unique identifiers without additional data and heuristics. The mapping is ambiguous by definition. The underlying flight plan standard were all created in an era of low memory machines, and when humans were expected to directly interpret data exactly as the programs represented it internally (because serialisation and de…
Earlier quoted context omitted.
How exactly would you do that? It’s impossible to map from a dataset of non-unique identifiers to unique identifiers without additional data and heuristics. The mapping is ambiguous by definition. The underlying flight plan standard were all created in an era of low memory machines, and when humans were expected to directly interpret data exactly as the programs represented it internally (because serialisation and de…
Couldn’t you use the surrounding points? Each point is surrounded by a set of nearby points. You can prepare a map of pairs of points into unique ids beforehand, then have a step that takes (before, current, after) for each point in the flight plan and finds the ID of current.