8 ms·

Why in the world is this even a problem? Shouldn't what's a taxiway and what's not be indicated on maps or diagrams or something that pilots can see?

Tuxer 9y ago
(pilot here) Yes, they are very well shown on maps, but it can be hard to map your diagram to what you're seeing, especially if it's raining or if it's at night, and even more if you're tired. I never made the mistake, but can see how somebody in bad conditions would.
- wfunction 9y ago
  Thanks! But why do you even have to map your diagram to what you're seeing? Isn't there a GPS system that shows you exactly where you are on the map and where you are going to go in the next few minutes? It doesn't seem like there should be any mental or visual processing to figure out that you're heading toward the wrong runway, right?
  - cyberferret 9y ago
    It's a matter of scale. Even on a modern HSI, the difference in distance between the runway and the parallel taxiway is probably the width of the indicator icon. Very hard to see on instruments. Much easier to see by looking out the windscreen.
    - wfunction 9y ago
      I can't tell if my expectations are just too high, but the impression I'm getting from all your answers is that pilots just don't have a dynamically updating (i.e. digital) map. It seems like everything is a bunch of numbers the poor pilots have to crunch or ticks that they have to count correctly or sheets of paper they have to pass to each other with diagrams. Why in the world is the system so ancient in 2017? Google Maps on my phone can show me where I am within 10 meters and where I'm going for the next 10 minutes, and it automatically zooms in and out at turning points... why can't an airplane have a display that shows them where they are and where they're going within the next minute?
      - cyberferret 9y ago
        Ironically, it is mainly because of reliability. Every system on an aircraft HAS to have double or triple redundancy by law, and a lot of these systems ARE antiquated by usual consumer standards. A lot of pilots these days have iPads in the cockpit to assist with this, but in nearly all airlines and aircraft types, these are unauthorised devices that are not part of the certification. Generally they are used for non critical things like manuals or checklists, but I know of pilots that use them for situational awareness as well. In an accident though, this may work against them, badly. Yes, it is the old legal and liability issue. Aircraft systems should be upgraded, but the cost of upgrading an entire fleet is prohibitive for most airlines that are already operating on the smell of an oily rag. New generation aircraft are getting better at it though. Like I mentioned before, I believe the 787 now has a HUD of sorts, which is long overdue.
        wfunction 9y ago
        Aw man, sad to read this but thank you.
        ajdlinux 9y ago
        Hmm, Electronic Flight Bags are now a regulator-approved thing for manuals/other paper products.
      - cyberferret 9y ago
        Oh, and aircraft DO have moving maps etc. now, but these are usually dialled out to show a range of hundreds of miles in cruise, and are not usually adjusted to show distances in mere metres when on final approach. Once again, because these displays are usually on the centre floor console or located below the HSI, they are outside the 'scan zone' of a pilot on short finals.
      - PhasmaFelis 9y ago
        In their defense, I would guess that making such a system 100% reliable and unintrusive may be a lot harder than we realize. It's not uncommon for Google Maps to be off by a few blocks for 10 seconds or more, and that could very easily be fatal if you're using it to land an airplane.
  - ubernostrum 9y ago
    Even setting aside the GPS/tablet/etc. question, I think you'd probably be astonished to learn how simple and how old the technology of automatic/instrument landing is. Instrument landing systems date to the 1920s, a time when flying at night, or above cloud tops, was incredibly dangerous. Imagine setting up a couple of directional radio antennas at the end of the runway. One broadcasts short beeps with long pauses (beep-----beep-----beep), the other broadcasts long beeps with short pauses (--beeeep--beeeep--). Set up the antennas so that if you're lined up horizontally with the center of the runway, the signals merge into a continuous tone (beeeeeeeeeeeeeeeeeep). That's more or less how instrument landing systems still work today. Modern ones have more antennas and coordinate you both vertically (on the correct slope to touch down at the start of the runway) and horizontally, but the whole thing is still based on directional radio signals that you pick up from your plane, and a published set of information for each airport (the "approach plate") telling you what frequencies to listen for depending on the runway you want. Airliners can be programmed to "autoland" based on this information, but it requires some setup and also requires the pilots to be ready to take over at a moment's notice (if, for example, controllers at the airport decide to have the plane land on a different runway).
  - Tuxer 9y ago
    There is, if you use it. In this case they were doing a visual approach , where you use eyesight in order to line up and land, because you have seen the runway. People do visual approaches in SFO as they are necessary to land 2 aircraft at the same time on the parallel runways ( they're like 30ft too close for parallel approaches on instrument ). It is still recommended to even in a visual approach, turn on the instrument approach systems ( for that exact reason ) but it looks like it is not mandatory for that airline.
cyberferret 9y ago
Because the pilot is almost never looking at a map on final approach. He is looking out the window, and in the dawn/dusk light, or with a setting sun in the background or inclement weather etc., a taxiway can look exactly like a runway. Don't forget that almost all taxiways run parallel to the runway, for about the same length. (NB: I used to be a commercial pilot.) In most airports I flew into, the surface material for the taxiways was different from the runway, so sometimes the taxiway could end up looking brighter and more prevalent than the runway under certain lighting conditions. Yep, I have had moments of confusion when on long finals into an unfamiliar airport. Never to the point of actually ending up landing on the taxiway, but the confusion is a thing that pilots have to contend with.
- willidiots 9y ago
  Seems like a design flaw. Do any taxiways have markings etc. to make them more distinguishable?
  - cyberferret 9y ago
    They do. They have different lighting systems/colours etc. to differentiate them. Taxiways generally have green lights along the centerline to guide aircraft rolling on the ground, but runways usually have white (bright) lights along the edges. There are times when even THAT causes confusion, because sometimes the taxiway centreline lights can look like the edge lights of the runway - especially if the light is refracting off a wet windscreen. So, in the end the problem is generally avoidable, but if you are on finals at a really busy airport after a gruelling 20 hours trans oceanic flight, at night, in the rain, and the tower is trying to hurry you up to expedite traffic, you can make mistakes.
    - kobeya 9y ago
      Seems like a very good argument for autopilot landings.
      - tjohns 9y ago
laydn 9y ago
If you watch any 28R approach video for SFO on YouTube, you'll be even more surprised. Because there is no way you can mistake the taxiway for the runway. There is a huge array of lights pointing the pilot towards the runway. I would imagine this would be more of a problem during the day because the lights are not as bright compared to the ambient light. I would think the best way to get this detected early would be to integrate some logic into the ATC radar. As the plane gets closer to the runway (or taxiway!), it should be easy to tell where the pilot is going by looking at the track and issue an automated warning.

Tuxer 9y ago

(pilot here) Yes, they are very well shown on maps, but it can be hard to map your diagram to what you're seeing, especially if it's raining or if it's at night, and even more if you're tired. I never made the mistake, but can see how somebody in bad conditions would.

wfunction 9y ago
Thanks! But why do you even have to map your diagram to what you're seeing? Isn't there a GPS system that shows you exactly where you are on the map and where you are going to go in the next few minutes? It doesn't seem like there should be any mental or visual processing to figure out that you're heading toward the wrong runway, right?
- cyberferret 9y ago
  It's a matter of scale. Even on a modern HSI, the difference in distance between the runway and the parallel taxiway is probably the width of the indicator icon. Very hard to see on instruments. Much easier to see by looking out the windscreen.
  - wfunction 9y ago
    I can't tell if my expectations are just too high, but the impression I'm getting from all your answers is that pilots just don't have a dynamically updating (i.e. digital) map. It seems like everything is a bunch of numbers the poor pilots have to crunch or ticks that they have to count correctly or sheets of paper they have to pass to each other with diagrams. Why in the world is the system so ancient in 2017? Google Maps on my phone can show me where I am within 10 meters and where I'm going for the next 10 minutes, and it automatically zooms in and out at turning points... why can't an airplane have a display that shows them where they are and where they're going within the next minute?
    - cyberferret 9y ago
      Ironically, it is mainly because of reliability. Every system on an aircraft HAS to have double or triple redundancy by law, and a lot of these systems ARE antiquated by usual consumer standards. A lot of pilots these days have iPads in the cockpit to assist with this, but in nearly all airlines and aircraft types, these are unauthorised devices that are not part of the certification. Generally they are used for non critical things like manuals or checklists, but I know of pilots that use them for situational awareness as well. In an accident though, this may work against them, badly. Yes, it is the old legal and liability issue. Aircraft systems should be upgraded, but the cost of upgrading an entire fleet is prohibitive for most airlines that are already operating on the smell of an oily rag. New generation aircraft are getting better at it though. Like I mentioned before, I believe the 787 now has a HUD of sorts, which is long overdue.
      - wfunction 9y ago
        Aw man, sad to read this but thank you.
      - ajdlinux 9y ago
        Hmm, Electronic Flight Bags are now a regulator-approved thing for manuals/other paper products.
    - cyberferret 9y ago
      Oh, and aircraft DO have moving maps etc. now, but these are usually dialled out to show a range of hundreds of miles in cruise, and are not usually adjusted to show distances in mere metres when on final approach. Once again, because these displays are usually on the centre floor console or located below the HSI, they are outside the 'scan zone' of a pilot on short finals.
    - PhasmaFelis 9y ago
      In their defense, I would guess that making such a system 100% reliable and unintrusive may be a lot harder than we realize. It's not uncommon for Google Maps to be off by a few blocks for 10 seconds or more, and that could very easily be fatal if you're using it to land an airplane.
- ubernostrum 9y ago
  Even setting aside the GPS/tablet/etc. question, I think you'd probably be astonished to learn how simple and how old the technology of automatic/instrument landing is. Instrument landing systems date to the 1920s, a time when flying at night, or above cloud tops, was incredibly dangerous. Imagine setting up a couple of directional radio antennas at the end of the runway. One broadcasts short beeps with long pauses (beep-----beep-----beep), the other broadcasts long beeps with short pauses (--beeeep--beeeep--). Set up the antennas so that if you're lined up horizontally with the center of the runway, the signals merge into a continuous tone (beeeeeeeeeeeeeeeeeep). That's more or less how instrument landing systems still work today. Modern ones have more antennas and coordinate you both vertically (on the correct slope to touch down at the start of the runway) and horizontally, but the whole thing is still based on directional radio signals that you pick up from your plane, and a published set of information for each airport (the "approach plate") telling you what frequencies to listen for depending on the runway you want. Airliners can be programmed to "autoland" based on this information, but it requires some setup and also requires the pilots to be ready to take over at a moment's notice (if, for example, controllers at the airport decide to have the plane land on a different runway).
- Tuxer 9y ago
  There is, if you use it. In this case they were doing a visual approach , where you use eyesight in order to line up and land, because you have seen the runway. People do visual approaches in SFO as they are necessary to land 2 aircraft at the same time on the parallel runways ( they're like 30ft too close for parallel approaches on instrument ). It is still recommended to even in a visual approach, turn on the instrument approach systems ( for that exact reason ) but it looks like it is not mandatory for that airline.

cyberferret 9y ago

Because the pilot is almost never looking at a map on final approach. He is looking out the window, and in the dawn/dusk light, or with a setting sun in the background or inclement weather etc., a taxiway can look exactly like a runway. Don't forget that almost all taxiways run parallel to the runway, for about the same length. (NB: I used to be a commercial pilot.) In most airports I flew into, the surface material for the taxiways was different from the runway, so sometimes the taxiway could end up looking brighter and more prevalent than the runway under certain lighting conditions. Yep, I have had moments of confusion when on long finals into an unfamiliar airport. Never to the point of actually ending up landing on the taxiway, but the confusion is a thing that pilots have to contend with.

willidiots 9y ago
Seems like a design flaw. Do any taxiways have markings etc. to make them more distinguishable?
- cyberferret 9y ago
  They do. They have different lighting systems/colours etc. to differentiate them. Taxiways generally have green lights along the centerline to guide aircraft rolling on the ground, but runways usually have white (bright) lights along the edges. There are times when even THAT causes confusion, because sometimes the taxiway centreline lights can look like the edge lights of the runway - especially if the light is refracting off a wet windscreen. So, in the end the problem is generally avoidable, but if you are on finals at a really busy airport after a gruelling 20 hours trans oceanic flight, at night, in the rain, and the tower is trying to hurry you up to expedite traffic, you can make mistakes.
  - kobeya 9y ago
    Seems like a very good argument for autopilot landings.
    - tjohns 9y ago

laydn 9y ago

If you watch any 28R approach video for SFO on YouTube, you'll be even more surprised. Because there is no way you can mistake the taxiway for the runway. There is a huge array of lights pointing the pilot towards the runway. I would imagine this would be more of a problem during the day because the lights are not as bright compared to the ambient light. I would think the best way to get this detected early would be to integrate some logic into the ATC radar. As the plane gets closer to the runway (or taxiway!), it should be easy to tell where the pilot is going by looking at the track and issue an automated warning.