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Planes use a system called TCAS to prevent collisions in the sky, this system is independent of ATC and works even if ATC is not paying attention or if pilots h

Planes use a system called TCAS to prevent collisions in the sky, this system is independent of ATC and works even if ATC is not paying attention or if pilots have the wrong frequency tuned. It detects impending collisions and gives both pilots clear and automated alerts plus an action IE climb + turn to execute immediately to prevent a collision. A similar system can and should be used for runways. As a thought experiment, imagine how many car accidents there would be if instead of traffic lights, each person had a AM radio in their car and police officers called out over the radio which cars should proceed across the intersection. That is the unfortunate state of modern? aviation.

ceejayoz 7mo ago
TCAS disables below 1,000 feet because there’s too much stuff at an airport.
- oceanplexian 7mo ago
  I have ADS-B in my airplane and can see everything on the ground on a pretty map as if it were literally a video game. I can see landing aircraft in realtime while holding short or crossing a runway. The emergency responder should have had it in their fire truck. The technology already exists. The problem has already been solved with an iPad and a $200 receiver. Almost certainly some BS regulation or rule was at least partially responsible here.
  - ceejayoz 7mo ago
    Information overload is a thing, and there are a lot of ground vehicles at a place like LGA.
    - fc417fc802 7mo ago
      Consider that if you have access to all the local ADS-B data you can project paths forward through 3D space for the next, say, 30 seconds or so. Using GPS you can determine your own position in 3D space. At that point it's trivial (and I'm not handwaving here, it is literally extremely trivial) to filter projected paths based on passing close enough to your own in 3D space (ie accounting for altitude). Stick that on a tablet and require it to be present in all vehicles that operate on the tarmac. It wouldn't need to work 100% of the time because you'd still be required to contact ATC. The only requirement is that it have a reasonably high chance of alerting drivers to potential mistakes before they happen. Which is to say this incident was trivially preventable had anyone with authority over these sorts of things cared to bother.
      - ceejayoz 7mo ago
        > for the next, say, 30 seconds or so But this is a hand-wave. This is a situation where both vehicles got explicit permission from someone who's supposed to know what they're doing. These sorts of runway crossings aren't unusual - and this one was responding to an emergency - and at a place like LGA there's always gonna be a plane on approach. The difference between "hold short at runway 22" and being on runway 22 is much less than 30 seconds in some cases.
        throw0101d 7mo ago
        I think the most generous interpretation of using 'all' ADS-B data (including things on the ground) would be to have VR and have boxes for all objects, à la the F-35 helmet: * https://www.radiantvisionsystems.com/blog/worlds-most-advanced-hmd https://www.radiantvisionsystems.com/blog/worlds-most-advanc... Not sure if you can do something on a 'simple' HUD that many planes have, so you could see objects in your flight path.
        fc417fc802 7mo ago
        The entire point is that there's no need for someone driving a ground vehicle to see all the ADS-B data. They only need to know if and when a plane is projected to cross the direction in which they're facing. It might also be useful to know the projected speed as well as how far in front of your vehicle it will pass (but you can presumably figure the latter out on your own because, y'know, the runway).
        fc417fc802 7mo ago
        If ATC says you're clear to cross the runway and then you glance down and the screen shows a plane projected to cross directly in front of you in 10 seconds you'd probably think twice, right? This hypothetical cheap appliance has GPS and a compass and probably even a camera feed facing forward. It isn't a difficult technical problem to calculate the time offset at which the object traveling along the crosscutting path will pass in front of you. > The difference between "hold short at runway 22" and being on runway 22 is much less than 30 seconds in some cases. What is the typical minimum temporal separation? I would have expected at least 45 or 60 seconds given the cost of a plane and the imminent threat to life.
- aeternum 7mo ago
  Well imagine if we designed a TCAS-like system that did work below 1,000 feet!
  - ceejayoz 7mo ago
    TCAS is mostly "how close to another plane am I?" In flight, the answer really shouldn't ever be "less than 500 feet". During landing, the answer almost certainly will be "less than 500 feet"; a plane's queued up to enter the runway after you land, a ground vehicle is working on something near but not on the end of the runway, etc. It's a surprisingly tough challenge to solve a) reliably and b) in a way that doesn't cause a whole bunch of false go-arounds wreaking havoc on the busy airport.
    - aeternum 7mo ago
      It's a much easier challenge when every moving vehicle in the airport environment is issued a relatively exact clearance. The ATC clearance gives each vehicle a movement contract. It would be great if avionics actually took those into account. Avionics should help pilots ensure their vehicles don't break the contract and should also alert immediately if other vehicles have, or their velocity vector is such that they will violate the contract. IE braking rate is insufficient to stop before the hold short line. ATC computers should ensure no conflicting clearances are issued. None of that happens right now.

ceejayoz 7mo ago

TCAS disables below 1,000 feet because there’s too much stuff at an airport.

oceanplexian 7mo ago
I have ADS-B in my airplane and can see everything on the ground on a pretty map as if it were literally a video game. I can see landing aircraft in realtime while holding short or crossing a runway. The emergency responder should have had it in their fire truck. The technology already exists. The problem has already been solved with an iPad and a $200 receiver. Almost certainly some BS regulation or rule was at least partially responsible here.
- ceejayoz 7mo ago
  Information overload is a thing, and there are a lot of ground vehicles at a place like LGA.
  - fc417fc802 7mo ago
    Consider that if you have access to all the local ADS-B data you can project paths forward through 3D space for the next, say, 30 seconds or so. Using GPS you can determine your own position in 3D space. At that point it's trivial (and I'm not handwaving here, it is literally extremely trivial) to filter projected paths based on passing close enough to your own in 3D space (ie accounting for altitude). Stick that on a tablet and require it to be present in all vehicles that operate on the tarmac. It wouldn't need to work 100% of the time because you'd still be required to contact ATC. The only requirement is that it have a reasonably high chance of alerting drivers to potential mistakes before they happen. Which is to say this incident was trivially preventable had anyone with authority over these sorts of things cared to bother.
    - ceejayoz 7mo ago
      > for the next, say, 30 seconds or so But this is a hand-wave. This is a situation where both vehicles got explicit permission from someone who's supposed to know what they're doing. These sorts of runway crossings aren't unusual - and this one was responding to an emergency - and at a place like LGA there's always gonna be a plane on approach. The difference between "hold short at runway 22" and being on runway 22 is much less than 30 seconds in some cases.
      - throw0101d 7mo ago
        I think the most generous interpretation of using 'all' ADS-B data (including things on the ground) would be to have VR and have boxes for all objects, à la the F-35 helmet: * https://www.radiantvisionsystems.com/blog/worlds-most-advanced-hmd https://www.radiantvisionsystems.com/blog/worlds-most-advanc... Not sure if you can do something on a 'simple' HUD that many planes have, so you could see objects in your flight path.
        fc417fc802 7mo ago
        The entire point is that there's no need for someone driving a ground vehicle to see all the ADS-B data. They only need to know if and when a plane is projected to cross the direction in which they're facing. It might also be useful to know the projected speed as well as how far in front of your vehicle it will pass (but you can presumably figure the latter out on your own because, y'know, the runway).
      - fc417fc802 7mo ago
        If ATC says you're clear to cross the runway and then you glance down and the screen shows a plane projected to cross directly in front of you in 10 seconds you'd probably think twice, right? This hypothetical cheap appliance has GPS and a compass and probably even a camera feed facing forward. It isn't a difficult technical problem to calculate the time offset at which the object traveling along the crosscutting path will pass in front of you. > The difference between "hold short at runway 22" and being on runway 22 is much less than 30 seconds in some cases. What is the typical minimum temporal separation? I would have expected at least 45 or 60 seconds given the cost of a plane and the imminent threat to life.
aeternum 7mo ago
Well imagine if we designed a TCAS-like system that did work below 1,000 feet!
- ceejayoz 7mo ago
  TCAS is mostly "how close to another plane am I?" In flight, the answer really shouldn't ever be "less than 500 feet". During landing, the answer almost certainly will be "less than 500 feet"; a plane's queued up to enter the runway after you land, a ground vehicle is working on something near but not on the end of the runway, etc. It's a surprisingly tough challenge to solve a) reliably and b) in a way that doesn't cause a whole bunch of false go-arounds wreaking havoc on the busy airport.
  - aeternum 7mo ago
    It's a much easier challenge when every moving vehicle in the airport environment is issued a relatively exact clearance. The ATC clearance gives each vehicle a movement contract. It would be great if avionics actually took those into account. Avionics should help pilots ensure their vehicles don't break the contract and should also alert immediately if other vehicles have, or their velocity vector is such that they will violate the contract. IE braking rate is insufficient to stop before the hold short line. ATC computers should ensure no conflicting clearances are issued. None of that happens right now.