4 ms·

I'll play devil's advocate and suggest that it is a systems error that the 777 accepted an altitude of 0 without sounding an alarm or at least requiring prior c

I'll play devil's advocate and suggest that it is a systems error that the 777 accepted an altitude of 0 without sounding an alarm or at least requiring prior confirmation. It shouldn't be that easy to almost total the airplane.

CamperBob2 5y ago
I don't understand why the automation feature in question is even available during takeoff. What would be a situation in which use of the FD at this point in the flight would be a preferable option?
- woofcat 5y ago
  IFR?
  - CamperBob2 5y ago
    IFR doesn't mean "Let go of the controls and let HAL sort it out." This equipment seems like it's meant to assist with pilot duties, not dictate to them.
jackweirdy 5y ago
Bear in mind there are airports in the world at less than 0ft sea level. Very complicated to validate what a valid input actually is
- nexuist 5y ago
  While true, my understanding is that the altimeters automatically calibrate themselves to air pressure as well as use auxiliary readings from the radio altimeter to provide an altitude system where 0ft is sea level, always. However given that the pilots seemingly didn't follow the pre-flight checklist it's possible they did not calibrate the altimeter either.
  - jackweirdy 5y ago
    Altimeters are only pilot calibrated to ensure planes travelling in various directions can trust their vertical separation is constant even amid rising or dropping temperatures and pressures. In that context an altimeter that calibrates itself is quite undesirable There is the radio-altimeter which uses ground based radar but that is for spoken-aloud altitude readouts and terrain warnings and as far as I’m aware doesn’t factor in Boeing or airbus autopilot. At least in the U.K., the lingo has us refer to this always as height (ie, above the ground) and not altitude (within the air above a hypothetical sea level)
- GekkePrutser 5y ago
  Amsterdam represent! :)
  - jacquesm 5y ago
    Amsterdam is pretty mild in comparison to Bar Yehuda, which is a good 375 meters below sea level. https://en.wikipedia.org/wiki/Bar_Yehuda_Airfield https://en.wikipedia.org/wiki/Bar_Yehuda_Airfield
    - GekkePrutser 5y ago
      Cool I didn't know that, thanks!
- thurn 5y ago
  do they not have GPS and the ability to look up airport elevations on a map?
- manojlds 5y ago
  The plane can't know by itself what altitude it is and at least provide warning to override what it thinks it is?
kortilla 5y ago
There are all kinds of airports at altitude 0. You’re arguing for vastly more complexity in the flight director for it to know what altitudes are valid for particular locations. > It shouldn't be that easy to almost total the airplane. It’s not, the pilots are complete fucking morons who ignored multiple checklists and basic knowledge about flying (210 knots on the ground is insane). This wasn’t autopilot or anything like that. It’s just hints for an already manual operation.
- tgsovlerkhgsel 5y ago
  > You’re arguing for vastly more complexity in the flight director The airplane should already have a terrain database in the ground proximity warning system, so triggering a warning in this case doesn't seem entirely unreasonable, should have very low false positives, and could improve flight safety. Should it be necessary? Theoretically not, but pilots are human, and we have to choose whether we want to be smug about their stupidity while piecing together 300+ charred corpses, or account for humans doing human things.
jacquesm 5y ago
It can go a lot lower than zero, and there are quite a few airfields where this matters: https://aviation.stackexchange.com/questions/56894/why-is-0-ft-a-valid-target-altitude-for-an-autopilot https://aviation.stackexchange.com/questions/56894/why-is-0-... Besides: you can't fix stupid, if someone switches on the autopilot seconds after wheels up without checking what altitude it is set for it could be anything, including below ground level. Autopilots aren't magic, and pilots have a very large amount of discretion in how they fly the airplane, but these pilots weren't really prepared to fly the plane for one second more than they had to. There is a reason they got sacked. Oh, and as to this being a Boeing issue: this setting can be entered on any autopilot. I'm all for giving Boeing shit when they are the ones that messed up but here they didn't.

CamperBob2 5y ago

I don't understand why the automation feature in question is even available during takeoff. What would be a situation in which use of the FD at this point in the flight would be a preferable option?

woofcat 5y ago
IFR?
- CamperBob2 5y ago
  IFR doesn't mean "Let go of the controls and let HAL sort it out." This equipment seems like it's meant to assist with pilot duties, not dictate to them.

jackweirdy 5y ago

Bear in mind there are airports in the world at less than 0ft sea level. Very complicated to validate what a valid input actually is

nexuist 5y ago
While true, my understanding is that the altimeters automatically calibrate themselves to air pressure as well as use auxiliary readings from the radio altimeter to provide an altitude system where 0ft is sea level, always. However given that the pilots seemingly didn't follow the pre-flight checklist it's possible they did not calibrate the altimeter either.
- jackweirdy 5y ago
  Altimeters are only pilot calibrated to ensure planes travelling in various directions can trust their vertical separation is constant even amid rising or dropping temperatures and pressures. In that context an altimeter that calibrates itself is quite undesirable There is the radio-altimeter which uses ground based radar but that is for spoken-aloud altitude readouts and terrain warnings and as far as I’m aware doesn’t factor in Boeing or airbus autopilot. At least in the U.K., the lingo has us refer to this always as height (ie, above the ground) and not altitude (within the air above a hypothetical sea level)
GekkePrutser 5y ago
Amsterdam represent! :)
- jacquesm 5y ago
  Amsterdam is pretty mild in comparison to Bar Yehuda, which is a good 375 meters below sea level. https://en.wikipedia.org/wiki/Bar_Yehuda_Airfield https://en.wikipedia.org/wiki/Bar_Yehuda_Airfield
  - GekkePrutser 5y ago
    Cool I didn't know that, thanks!
thurn 5y ago
do they not have GPS and the ability to look up airport elevations on a map?
manojlds 5y ago
The plane can't know by itself what altitude it is and at least provide warning to override what it thinks it is?

kortilla 5y ago

There are all kinds of airports at altitude 0. You’re arguing for vastly more complexity in the flight director for it to know what altitudes are valid for particular locations. > It shouldn't be that easy to almost total the airplane. It’s not, the pilots are complete fucking morons who ignored multiple checklists and basic knowledge about flying (210 knots on the ground is insane). This wasn’t autopilot or anything like that. It’s just hints for an already manual operation.

tgsovlerkhgsel 5y ago
> You’re arguing for vastly more complexity in the flight director The airplane should already have a terrain database in the ground proximity warning system, so triggering a warning in this case doesn't seem entirely unreasonable, should have very low false positives, and could improve flight safety. Should it be necessary? Theoretically not, but pilots are human, and we have to choose whether we want to be smug about their stupidity while piecing together 300+ charred corpses, or account for humans doing human things.

jacquesm 5y ago

It can go a lot lower than zero, and there are quite a few airfields where this matters: https://aviation.stackexchange.com/questions/56894/why-is-0-ft-a-valid-target-altitude-for-an-autopilot https://aviation.stackexchange.com/questions/56894/why-is-0-... Besides: you can't fix stupid, if someone switches on the autopilot seconds after wheels up without checking what altitude it is set for it could be anything, including below ground level. Autopilots aren't magic, and pilots have a very large amount of discretion in how they fly the airplane, but these pilots weren't really prepared to fly the plane for one second more than they had to. There is a reason they got sacked. Oh, and as to this being a Boeing issue: this setting can be entered on any autopilot. I'm all for giving Boeing shit when they are the ones that messed up but here they didn't.