4 ms·

GPS is not essential to air navigation. It’s nice to have, and there are some approaches that legally require it to be operational in order to fly them (IFR pro

by K0balt 2mo ago

GPS is not essential to air navigation. It’s nice to have, and there are some approaches that legally require it to be operational in order to fly them (IFR procedures) but aviation has other systems in place to guide aircraft under conditions where visual flight navigation is impossible. In this case, IMHO, the pilots had become complacent and lax in their navigational rigor because of the fact that GPS makes a lot of the slightly less automated systems unnecessary, and people get used to that workflow. If the flight crew had been looking at their map and using it to inform them about the mountains in their path, fixing position by the VOR and DME, or even just a stopwatch and compass heading, they would have easily known they needed to be at a higher altitude. Not being precisely sure of their exact position, they should have at least been maintaining the minimum safe altitude for the area they knew they were in. But unfortunately, people get so used to looking at the shiny screen giving them effortless situational awareness that they forget all of the rules and habits that kept pilots alive for the last century before glass cockpits were a thing, and they forget that mountains are the tigers of the air, always waiting to catch pilots unaware. This is a useful cautionary tale not only for pilots, but increasingly for humans in general as we become accustomed to a new kind of instrument that allows us to offload a great deal of our cognitive focus to a tool that may sometimes fail.

scrlk 2mo ago
To add to this, there's a good lecture called Children of the Magenta Line that discusses automation dependency: https://www.youtube.com/watch?v=5ESJH1NLMLs https://www.youtube.com/watch?v=5ESJH1NLMLs
- teddyh 2mo ago
  Better version: <https://www.youtube.com/watch?v=lIusD6Z-3cU https://www.youtube.com/watch?v=lIusD6Z-3cU>
lbriner 2mo ago
This was the partial cause of Air France 447. Pilots were so used to "the plane won't make a mistake" that they were not aware/not trained properly about things that are nothing to do with the FMS like frozen pitot tubes and also that the autopilot has a number of "modes" which mean you need to go back to basics like altitude, attitude and air speed.
- p-e-w 2mo ago
  If it’s true that other navigation systems are as safe and capable as GPS, then GPS navigation should be randomly disabled in every aircraft occasionally to ensure that pilots remain fluent in using them. If it isn’t true, then the military is partially responsible for the crash of this aircraft.
  - streetfighter64 2mo ago
    No, pilots should ensure they're current at navigating without GPS because it can fail, just like pilots practice engine failure procedures and every other emergency / non-normal procedure. That doesn't mean it should be "randomly disabled" for the same reason that you don't test software in production or randomly turn off the engine of the plane. Obviously.
    - genxy 2mo ago
      We don't know how it failed. Maybe it displayed their lat/long perfectly but at the wrong altitude. We think of failure as obvious, but it is often nearly impossible to tell unless you are looking for it.
      - parineum 2mo ago
        GPS is a 3D measurement.
        thrill 2mo ago
        Errors can be along any axis, random, infrequent, drifting, and nonobvious.
      - wat10000 2mo ago
        Altitude is the least accurate dimension for GPS, and it's also the one dimension that's provided with great accuracy by a really simple mechanical gauge present in every aircraft. There should never be a situation where an incorrect altitude figure from GPS causes a problem.
Suzuran 2mo ago
Don't worry, our government is doing their level best to make GPS the only option for air navigation. After all, we all know that technology NEVER fails, and the sooner we can turn off all those big bad old ground radars and navigation aids, the sooner we can sell all that real estate and use the money for things that the American public desperately needs, like more corporate bailouts and bathroom security cameras.
- tclancy 2mo ago
  They’re going to eliminate windows?
  - gpm 2mo ago
    The weather already does that on a regular basis... though they are doing their best to make the weather, on average (i.e. what you might call a climate), worse.
    - parineum 2mo ago
      Worse is a value judgement and, in context, the value would be "ability to fly by sight". Is climate change going to make it more difficult to see outside?
      - gpm 2mo ago
        The value here is pretty simple, the frequency at which windows are rendered useless due to weather. Yes, the change we are undergoing and that the current administration seems to be doing their best to accelerate includes an increase in heavy precipitation across north america.
        merely-unlikely 2mo ago
        That's good news for the data centers.
inigyou 2mo ago
I thought they were shutting down VORs to save money and relying more and more on RNAV (i.e. GPS) approaches.
jillesvangurp 2mo ago
Depends on the weather. A lot of approaches to airports are GPS only these days. If GPS doesn't work and you are not in VFR weather, you can't fly those approaches. In bad weather you'd be diverting to an airport that still has ILS. Vectoring by the controller to a visual or ILS approach still works but they'd be juggling a lot of planes. And while lots of the bigger/older airports still have ILS, many VORs and DMEs are being retired and many smaller airports don't have ILS at all. Denied access to GPS in a large area in bad weather would likely result in lots of flight cancellations and contingency plans getting put in motion to get anything still in the air landed safely. But controllers would get very busy and ILS runways very congested. Here in Europe, there have been a few cases of GPS denied areas especially closer to Russia. Mostly pilots and controllers at e.g. Helsinki airport are able to deal with this.
- K0balt 2mo ago
  lol the very first paragraph of my comment. But yeah, IFR is getting more dependent on gps approaches… which is incredibly stupid because it becomes trivial to disrupt air navigation. It’s a bit better with newer chipsets that support GPS, Galileo, GLONASS, and BeiDou… but I’d venture that when the military is jamming I’d does them all. I can buy a jammer that will take out GPS over about a kilometer for less than $1k. They are used all over the place by criminals in many countries, because there often aren’t standardized addresses and if your drug house can’t be located on gps in the favella, you get a lot more warning before a raid. That same transmitter with a directional antenna could knock out a 10 degree sector for 30km. VMC prevailed at the time of the accident, although it was a dark moonless night. The flight in question only needed to maintain an altitude above the mountains until a visual to the airport was established along with their distance from the runway. My guess based on the flight path is they had a visual on the airport but were lost and didn’t know where they were. If the gps hadn’t come back on for a minute they probably would have been fine, but it came back on and they fixated on the shiny screen instead of using their navigation skills. Unless you want trust your life to an instrument, you fly like it might not be trustworthy. Granted, there are many instruments in an airplane we trust our lives to, but they can mostly be cross-referenced against other inputs. The trouble with gps is that it enables procedures that make that essentially impossible, and the major failure mode is not one you can carry an extra for. In aviation, situational awareness is life.
VBprogrammer 2mo ago
> GPS is not essential to air navigation. It’s nice to have, and there are some approaches that legally require it to be operational in order to fly them (IFR procedures) but aviation has other systems in place to guide aircraft under conditions where visual flight navigation is impossible. This has not been the practical reality for many years for IFR flights (arguably not for VFR flight either but some of the good old boys will still argue that you should still be using a map and compass). In Europe the minimum requirement has been B-RNAV and aircraft are controlled with reference to intersections which have no defined relationships with underlying VORs, and an expectation of being able to navigate direct to one from any arbitrary point in space. Airliners generally get away with this because they have DME-DME disciplined INS. Smaller aircraft, well the backup is vectors from ATC.
- dmitrygr 2mo ago
  Does Europe not have VORs?
  - VBprogrammer 2mo ago
    Of course - though many of them have been decommissioned or are in the process. Though recent developments have probably reduced the enthusiasm for removing them so quickly. However, that doesn't change the fact that the intersection that ATC are flying you towards are actually now defined as coordinates, not radials or distances from nearby VORs. If an ATC tells you "direct OKSAW" they won't give you a VOR radial to intercept - you are expected to go straight there in a relatively straight line from your current position. There were boxes like the KNS80 that could do VOR-VOR navigation to do this kind of thing but it's not user friendly by modern standards.
    - dmitrygr 2mo ago
      When you file your flight plan, there is a box for "equipment". Put "O" there and they will not do that to you anymore. "DO" if you have DME.
      - 2mo ago

by K0balt 2mo ago

scrlk 2mo ago

To add to this, there's a good lecture called Children of the Magenta Line that discusses automation dependency: https://www.youtube.com/watch?v=5ESJH1NLMLs https://www.youtube.com/watch?v=5ESJH1NLMLs

teddyh 2mo ago
Better version: <https://www.youtube.com/watch?v=lIusD6Z-3cU https://www.youtube.com/watch?v=lIusD6Z-3cU>

lbriner 2mo ago

This was the partial cause of Air France 447. Pilots were so used to "the plane won't make a mistake" that they were not aware/not trained properly about things that are nothing to do with the FMS like frozen pitot tubes and also that the autopilot has a number of "modes" which mean you need to go back to basics like altitude, attitude and air speed.

p-e-w 2mo ago
If it’s true that other navigation systems are as safe and capable as GPS, then GPS navigation should be randomly disabled in every aircraft occasionally to ensure that pilots remain fluent in using them. If it isn’t true, then the military is partially responsible for the crash of this aircraft.
- streetfighter64 2mo ago
  No, pilots should ensure they're current at navigating without GPS because it can fail, just like pilots practice engine failure procedures and every other emergency / non-normal procedure. That doesn't mean it should be "randomly disabled" for the same reason that you don't test software in production or randomly turn off the engine of the plane. Obviously.
  - genxy 2mo ago
    We don't know how it failed. Maybe it displayed their lat/long perfectly but at the wrong altitude. We think of failure as obvious, but it is often nearly impossible to tell unless you are looking for it.
    - parineum 2mo ago
      GPS is a 3D measurement.
      - thrill 2mo ago
        Errors can be along any axis, random, infrequent, drifting, and nonobvious.
    - wat10000 2mo ago
      Altitude is the least accurate dimension for GPS, and it's also the one dimension that's provided with great accuracy by a really simple mechanical gauge present in every aircraft. There should never be a situation where an incorrect altitude figure from GPS causes a problem.

Suzuran 2mo ago

Don't worry, our government is doing their level best to make GPS the only option for air navigation. After all, we all know that technology NEVER fails, and the sooner we can turn off all those big bad old ground radars and navigation aids, the sooner we can sell all that real estate and use the money for things that the American public desperately needs, like more corporate bailouts and bathroom security cameras.

tclancy 2mo ago
They’re going to eliminate windows?
- gpm 2mo ago
  The weather already does that on a regular basis... though they are doing their best to make the weather, on average (i.e. what you might call a climate), worse.
  - parineum 2mo ago
    Worse is a value judgement and, in context, the value would be "ability to fly by sight". Is climate change going to make it more difficult to see outside?
    - gpm 2mo ago
      The value here is pretty simple, the frequency at which windows are rendered useless due to weather. Yes, the change we are undergoing and that the current administration seems to be doing their best to accelerate includes an increase in heavy precipitation across north america.
      - merely-unlikely 2mo ago
        That's good news for the data centers.

inigyou 2mo ago

I thought they were shutting down VORs to save money and relying more and more on RNAV (i.e. GPS) approaches.

jillesvangurp 2mo ago

Depends on the weather. A lot of approaches to airports are GPS only these days. If GPS doesn't work and you are not in VFR weather, you can't fly those approaches. In bad weather you'd be diverting to an airport that still has ILS. Vectoring by the controller to a visual or ILS approach still works but they'd be juggling a lot of planes. And while lots of the bigger/older airports still have ILS, many VORs and DMEs are being retired and many smaller airports don't have ILS at all. Denied access to GPS in a large area in bad weather would likely result in lots of flight cancellations and contingency plans getting put in motion to get anything still in the air landed safely. But controllers would get very busy and ILS runways very congested. Here in Europe, there have been a few cases of GPS denied areas especially closer to Russia. Mostly pilots and controllers at e.g. Helsinki airport are able to deal with this.

K0balt 2mo ago
lol the very first paragraph of my comment. But yeah, IFR is getting more dependent on gps approaches… which is incredibly stupid because it becomes trivial to disrupt air navigation. It’s a bit better with newer chipsets that support GPS, Galileo, GLONASS, and BeiDou… but I’d venture that when the military is jamming I’d does them all. I can buy a jammer that will take out GPS over about a kilometer for less than $1k. They are used all over the place by criminals in many countries, because there often aren’t standardized addresses and if your drug house can’t be located on gps in the favella, you get a lot more warning before a raid. That same transmitter with a directional antenna could knock out a 10 degree sector for 30km. VMC prevailed at the time of the accident, although it was a dark moonless night. The flight in question only needed to maintain an altitude above the mountains until a visual to the airport was established along with their distance from the runway. My guess based on the flight path is they had a visual on the airport but were lost and didn’t know where they were. If the gps hadn’t come back on for a minute they probably would have been fine, but it came back on and they fixated on the shiny screen instead of using their navigation skills. Unless you want trust your life to an instrument, you fly like it might not be trustworthy. Granted, there are many instruments in an airplane we trust our lives to, but they can mostly be cross-referenced against other inputs. The trouble with gps is that it enables procedures that make that essentially impossible, and the major failure mode is not one you can carry an extra for. In aviation, situational awareness is life.

VBprogrammer 2mo ago

> GPS is not essential to air navigation. It’s nice to have, and there are some approaches that legally require it to be operational in order to fly them (IFR procedures) but aviation has other systems in place to guide aircraft under conditions where visual flight navigation is impossible. This has not been the practical reality for many years for IFR flights (arguably not for VFR flight either but some of the good old boys will still argue that you should still be using a map and compass). In Europe the minimum requirement has been B-RNAV and aircraft are controlled with reference to intersections which have no defined relationships with underlying VORs, and an expectation of being able to navigate direct to one from any arbitrary point in space. Airliners generally get away with this because they have DME-DME disciplined INS. Smaller aircraft, well the backup is vectors from ATC.

dmitrygr 2mo ago
Does Europe not have VORs?
- VBprogrammer 2mo ago
  Of course - though many of them have been decommissioned or are in the process. Though recent developments have probably reduced the enthusiasm for removing them so quickly. However, that doesn't change the fact that the intersection that ATC are flying you towards are actually now defined as coordinates, not radials or distances from nearby VORs. If an ATC tells you "direct OKSAW" they won't give you a VOR radial to intercept - you are expected to go straight there in a relatively straight line from your current position. There were boxes like the KNS80 that could do VOR-VOR navigation to do this kind of thing but it's not user friendly by modern standards.
  - dmitrygr 2mo ago
    When you file your flight plan, there is a box for "equipment". Put "O" there and they will not do that to you anymore. "DO" if you have DME.
    - 2mo ago