5 ms·

It sounds like no one system of keeping the plane level is fool & error proof. OK, this might be a stupid idea, but what about a simple old spirit level, a fan

It sounds like no one system of keeping the plane level is fool & error proof. OK, this might be a stupid idea, but what about a simple old spirit level, a fancy oil based one that will never freeze, mounted to the side of the cockpit to give the pilots a emergency true level backup when all else fails?

taneq 8y ago
It'd work fine if the plane was stationary but the moment you have any acceleration, you couldn't trust it.
- acqq 8y ago
  During one train travel I've watched one window filled with a few inches of water between the two glass planes. If you'd trust that one alone, the train went more than 45 degrees up or down when it was actually traveling on the flat ground, but changing the speed.
bnt 8y ago
Are you just copy/pasting this across different discussions on this topic? While I personally like the proposal (I am no pilot so it may be a dumb idea to a professional), c/p the same post is just noise.
- OscarTheGrinch 8y ago
  Sorry, just trying to maximize the chance of getting an answer.
  - pferde 8y ago
    So, basically the same approach that spammers use - maximizing your gain while inconveniencing everyone else. I hope you're proud of yourself.
    - seppin 8y ago
      Well, what does he have to lose?
      - OscarTheGrinch 8y ago
        karma
cm2187 8y ago
I would rather expect the anti-stall system to be based on a speed indicator rather than a level indicator. Though not an aviation specialist.
- isostatic 8y ago
  I think it needs to be both - air speed and angle of attack.
- cyberferret 8y ago
  Stalls can be induced both ways - angle of attack and/or speed. Usually a combination of both.
- mannykannot 8y ago
  Beyond the point, made by others, that a spirit level will not give you the airplane's attitude (on account of acceleration), it is also the case that the airplane's attitude does not tell you the angle of attack, which also depends on the airplane's vertical speed with respect to the airmass. Pilots-in-training are taught not to rely on the airplane's attitude (normally judged, in visual flight, by the position of the nose or top of the instrument panel relative to the horizon) as an indicator of whether a stall is imminent. In a steady state, and for a given wing configuration (flaps/slats/spoiler positions), there's a causal relationship between angle of attack and speed (which also depends on air density, aircraft weight and load factor (how many gs you are pulling)), such that the indicated airspeed (which measures ram air pressure in a pitot tube, and fortuitously cancels out the density dependence) has historically been the proxy for angle of attack - and, at least in small airplanes, it still is. Even small airplanes often have a separate stall warning device, which is triggered by the movement of the leading-edge stagnation point (where the flow divides between going above and below the wing) as the angle of attack changes. In its simplest form, it is operated by a small tab which is flipped up when the stagnation point moves below it.
tapland 8y ago
Look up the pilot running a few different level meters when debunking a flat earthers on YouTube. On mobile but will see if I can link later. Normal levels don't work well at all on planes.
cyberferret 8y ago
The instrument panels on old beater Cessnas, Pipers etc. have a 'slip ball' on the turn indicator which is basically a small ball in liquid. But that shows if the plane is laterally out of balance during a turn. It is about the only gravity based instrument on the aircraft (because ideally, you would want to keep a steady 1G straight towards the floor of the plane during a turn for passenger comfort). All other instruments that relate to orientation are gyroscope based, so they constantly reference a point in infinite space. When you are being thrown about in turbulence, or a tight turn, gravity based instrumentation will be all over the place and give false readings. Pretty much exactly why IFR (instrument flying) rated pilots are trained NOT to rely on the inner ear balance systems to know if they are flying straight and level etc. because the inner ear fluids can be easily tricked by standard flying manoeuvres into thinking you are in a screaming right hand dive when you are in a gentle left hand turn (if you don't have a visual reference to corroborate).
deleted 8y ago
[deleted]
mannykannot 8y ago
Firstly, let's note that the cause of the Ethiopian Airlines crash has not yet been determined. In the case of the Lion Air crash, the problem was not that the crew were unaware of the airplane's attitude (it was daylight in good weather, and they also had functioning airspeed indicators), it was that the control system kept resetting the longitudinal trim incorrectly in response to a faulty angle-of-attack sensor, and the crew did not follow the procedure to disable it from doing so.

taneq 8y ago

It'd work fine if the plane was stationary but the moment you have any acceleration, you couldn't trust it.

acqq 8y ago
During one train travel I've watched one window filled with a few inches of water between the two glass planes. If you'd trust that one alone, the train went more than 45 degrees up or down when it was actually traveling on the flat ground, but changing the speed.

bnt 8y ago

Are you just copy/pasting this across different discussions on this topic? While I personally like the proposal (I am no pilot so it may be a dumb idea to a professional), c/p the same post is just noise.

OscarTheGrinch 8y ago
Sorry, just trying to maximize the chance of getting an answer.
- pferde 8y ago
  So, basically the same approach that spammers use - maximizing your gain while inconveniencing everyone else. I hope you're proud of yourself.
  - seppin 8y ago
    Well, what does he have to lose?
    - OscarTheGrinch 8y ago
      karma

cm2187 8y ago

I would rather expect the anti-stall system to be based on a speed indicator rather than a level indicator. Though not an aviation specialist.

isostatic 8y ago
I think it needs to be both - air speed and angle of attack.
cyberferret 8y ago
Stalls can be induced both ways - angle of attack and/or speed. Usually a combination of both.
mannykannot 8y ago
Beyond the point, made by others, that a spirit level will not give you the airplane's attitude (on account of acceleration), it is also the case that the airplane's attitude does not tell you the angle of attack, which also depends on the airplane's vertical speed with respect to the airmass. Pilots-in-training are taught not to rely on the airplane's attitude (normally judged, in visual flight, by the position of the nose or top of the instrument panel relative to the horizon) as an indicator of whether a stall is imminent. In a steady state, and for a given wing configuration (flaps/slats/spoiler positions), there's a causal relationship between angle of attack and speed (which also depends on air density, aircraft weight and load factor (how many gs you are pulling)), such that the indicated airspeed (which measures ram air pressure in a pitot tube, and fortuitously cancels out the density dependence) has historically been the proxy for angle of attack - and, at least in small airplanes, it still is. Even small airplanes often have a separate stall warning device, which is triggered by the movement of the leading-edge stagnation point (where the flow divides between going above and below the wing) as the angle of attack changes. In its simplest form, it is operated by a small tab which is flipped up when the stagnation point moves below it.

tapland 8y ago

Look up the pilot running a few different level meters when debunking a flat earthers on YouTube. On mobile but will see if I can link later. Normal levels don't work well at all on planes.

cyberferret 8y ago

The instrument panels on old beater Cessnas, Pipers etc. have a 'slip ball' on the turn indicator which is basically a small ball in liquid. But that shows if the plane is laterally out of balance during a turn. It is about the only gravity based instrument on the aircraft (because ideally, you would want to keep a steady 1G straight towards the floor of the plane during a turn for passenger comfort). All other instruments that relate to orientation are gyroscope based, so they constantly reference a point in infinite space. When you are being thrown about in turbulence, or a tight turn, gravity based instrumentation will be all over the place and give false readings. Pretty much exactly why IFR (instrument flying) rated pilots are trained NOT to rely on the inner ear balance systems to know if they are flying straight and level etc. because the inner ear fluids can be easily tricked by standard flying manoeuvres into thinking you are in a screaming right hand dive when you are in a gentle left hand turn (if you don't have a visual reference to corroborate).

deleted 8y ago

[deleted]

mannykannot 8y ago

Firstly, let's note that the cause of the Ethiopian Airlines crash has not yet been determined. In the case of the Lion Air crash, the problem was not that the crew were unaware of the airplane's attitude (it was daylight in good weather, and they also had functioning airspeed indicators), it was that the control system kept resetting the longitudinal trim incorrectly in response to a faulty angle-of-attack sensor, and the crew did not follow the procedure to disable it from doing so.