Why do airplanes have machinery to tell whether they are parallel to the ground?

On multiple places on the Flat-Earth Wiki, it is being stated that the horizon is always at your eye level:

A fact of basic perspective is that the line of the horizon is always at eye level with the observer.

If that's true, why can't pilots tell whether an airplane is parallel to the ground simply by looking where the horizon is? Why can't they simply make sure that the horizon is at the eye level?
An obvious answer seems to be that it won't work because the Earth is round and, at the 9'000 meters height (where some airplanes fly), the horizon is visibly below your eye level, 3.14 degrees below your eye level. Trying to align a high-flying airplane assuming the horizon is always at your eye level will crash an airplane.

And clouds.

And clouds.

OK, but what when there are no clouds? Why do pilots still rely on machinery, rather than trying to make the horizon fit their eye level?

And night.

And night.

At night, you can still see rather clearly where the horizon is: it's where the stars cease to be.

Quote from: Jura-Glenlivet II on September 01, 2023, 08:02:55 AM

And night.

At night, you can still see rather clearly where the horizon is: it's where the stars cease to be.

Not necessarily, FatAss.

You can't easily see the horizon at night if it's overcast and you are flying through clouds or over clouds, or there are storm clouds, or fog, or there are mountains ahead, or especially if it is a new moon.

When all of our instruments, today, and earlier, have been used, to measure things, etc. When we've used levels, or finding level within air, by the air pressure around planes, we cannot measure for level, beyond the plane itself, at one time, in flights.

Except for laser levels, of course, not used on planes, to measure for level flight in air.

How could we even MEASURE for a ball Earth's surface, being curved all over the surface below a plane in air? Make up a magical force that doesn't even EXIST, and make up whatever you want it to do, like changing what instruments read as level, as flat and horizontal, no problem at all, right?

The ball Earth lie, is purely made up nonsense.

When all of our instruments, today, and earlier, have been used, to measure things, etc. When we've used levels, or finding level within air, by the air pressure around planes, we cannot measure for level, beyond the plane itself, at one time, in flights.

Except for laser levels, of course, not used on planes, to measure for level flight in air.

How could we even MEASURE for a ball Earth's surface, being curved all over the surface below a plane in air? Make up a magical force that doesn't even EXIST, and make up whatever you want it to do, like changing what instruments read as level, as flat and horizontal, no problem at all, right?

The ball Earth lie, is purely made up nonsense.

Yes, yes, yes.

Heard it all before, turdonmybum2.

The horrible ball earth lie and all it's purely made up nonsense!

You just cough up a nice photo of the edge of the flat earth where the dome meets the ground, like a good little flat earth boy.......

Oh, cameras do work in your world, yes? Just checking, because I know telescopes don't.

By the way, how tall are you? You type like a midget, or a dwarf. There's no way you're taller than Michael J Fox that's for sure.

You just cough up a nice photo of the edge of the flat earth where the dome meets the ground, like a good little flat earth boy.......

Oh, cameras do work in your world, yes? Just checking, because I know telescopes don't.

I thought the excuse was the armed NASA contingent that controls the whole coastline of the ice wall.  How many miles of coastline would the ice wall have?  To encircle the known world? 

How could we even MEASURE for a ball Earth's surface, being curved all over the surface below a plane in air?

You only measure for the surface when you are going for a terrain based altitude such as landing.
Most of the time, you don't measure for the surface at all.
Instead, you measure for level.
When a plane flies over a hill, level doesn't magically align to that hill.

Quote from: Smock Latrine on September 02, 2023, 03:35:26 AM

You just cough up a nice photo of the edge of the flat earth where the dome meets the ground, like a good little flat earth boy.......

Oh, cameras do work in your world, yes? Just checking, because I know telescopes don't.

I thought the excuse was the armed NASA contingent that controls the whole coastline of the ice wall.  How many miles of coastline would the ice wall have?  To encircle the known world?

Turdonmybum2, forgets that flat earth with a dome meeting it, has literally thousands and thousands of kilometres of edge of Earth and edge of dome to examine and photograph.

He's never seen it, never examined it, never photographed it. No other person on Earth in the entire history of humans on Earth, has ever done any of these things either. No other person has even been stupid enough to try and fake seeing and photographing the edge of the world and edge of the sky dome. 

Yet, Turdonmybum2 is happy to call the globe earth model a nonsensical lie and anybody who subscribes to it, a gullible fool.

Turdonmybum2 needs to grow a pair of globes, buy a row boat, go to Antarctica, and bring us back a nice photo of the edge of the world, or forever keep his stupid baseless  opinions to himself. 

Quote from: turbonium2 on September 01, 2023, 09:14:08 PM

How could we even MEASURE for a ball Earth's surface, being curved all over the surface below a plane in air?

You only measure for the surface when you are going for a terrain based altitude such as landing.
Most of the time, you don't measure for the surface at all.
Instead, you measure for level.
When a plane flies over a hill, level doesn't magically align to that hill.

Obviously it doesn't do that, so why are you trying to imply that I DID say that?

Look back at my posts, and get a clue already, okay?

Planes measure for level within air, by measuring the air pressure around the plane, as I've told you over and over again already. You know that, so cut the BS, it's a waste of everyone's time, especially MINE!

On multiple places on the Flat-Earth Wiki, it is being stated that the horizon is always at your eye level:

Quote from: https://theflatearthsociety.org/tiki/tiki-index.php?page=Basic+Perspective

A fact of basic perspective is that the line of the horizon is always at eye level with the observer.

If that's true, why can't pilots tell whether an airplane is parallel to the ground simply by looking where the horizon is? Why can't they simply make sure that the horizon is at the eye level?
An obvious answer seems to be that it won't work because the Earth is round and, at the 9'000 meters height (where some airplanes fly), the horizon is visibly below your eye level, 3.14 degrees below your eye level. Trying to align a high-flying airplane assuming the horizon is always at your eye level will crash an airplane.

Because planes can fly at angles. After you adjust to angle less than 15 degrees (the point before true angular momentum sets in and things like trays start to slide), you need to be able to tell the angle of ascent or descent if the controls are too loose or something. It's also important to know if you're coming down at too hard an angle. But sure, blame RE for tool that basically means the difference between crashing and landing.

On multiple places on the Flat-Earth Wiki, it is being stated that the horizon is always at your eye level:

Quote from: https://theflatearthsociety.org/tiki/tiki-index.php?page=Basic+Perspective

A fact of basic perspective is that the line of the horizon is always at eye level with the observer.

If that's true, why can't pilots tell whether an airplane is parallel to the ground simply by looking where the horizon is? Why can't they simply make sure that the horizon is at the eye level?

What they mean is that the horizon adjusts to eye level. On a mountain? On the plains below. These two people see horizon straight out. But what your eyes see is completely unhelpful for traveling 14,000 ft up or so.

Quote from: bulmabriefs144 on September 03, 2023, 05:38:04 AM

Because planes can fly at angles. After you adjust to angle less than 15 degrees (the point before true angular momentum sets in and things like trays start to slide), you need to be able to tell the angle of ascent or descent if the controls are too loose or something. It's also important to know if you're coming down at too hard an angle.

You really don't know what you're talking about do you? You're what, 12 years old, you don't have flying experience, you are taking some kind of a guess as to how you think things work. Your guesses are mostly wrong.

You think this clueless kid is 12?? I had him pegged at single digits with a mouthful of rotting teeth and a bottle of mountain dew always in his hand. This dopey little bugger has clearly never been in a flight simulator, or played a video game as a pilot, flown a remote control plane, or likely even a paper plane that he has made himself.

Obviously it doesn't do that, so why are you trying to imply that I DID say that?

Because you complained about measuring for the curved surface of Earth.
Why be so dishonest talking about that when you fully know it doesn't measure for the surface of Earth?

Planes measure for level within air, by measuring the air pressure around the plane

No, that's altitude, not level.
But again, you know this. So why talk about trying to measure for a curved surface? It is just dishonest BS from you.

You know that, so cut the BS, it's a waste of everyone's time, especially MINE!

Because planes can fly at angles. After you adjust to angle less than 15 degrees (the point before true angular momentum sets in and things like trays start to slide), you need to be able to tell the angle of ascent or descent if the controls are too loose or something. It's also important to know if you're coming down at too hard an angle. But sure, blame RE for tool that basically means the difference between crashing and landing.

And the question is why do you need an artificial horizon, rather than a real horizon?
Why would the controls being too loose have any impact on this?
You are just making up whatever BS you can to pretend to have answers.

What they mean is that the horizon adjusts to eye level. On a mountain? On the plains below. These two people see horizon straight out. But what your eyes see is completely unhelpful for traveling 14,000 ft up or so.

Why?
If the horizon is at eye level at 14 000 ft; why can't a pilot use that to know they are flying level?


The reality is that the horizon is below eye level, and the amount it is below will increase as you get higher.
But the bigger issue was already raised, to be able to see it in any conditions.

No, that's altitude, not level.

No, they measure for BOTH level flight AND altitude, with instruments.

The only way we CAN measure for level flight, within air, is measuring the air pressure on the top and the bottom of the plane. The air above the flat Earth, flows over it flat layers, called pressure gradients. The instruments measure the air pressure within flights, and read O feet per minute as level flight. 1 or more feet per minute is an ascent, -1 or more feet is a descent.

If Earth was a ball, planes would be flying upward in level flights, which they don't, and prove that Earth is flat, when they land down 2000 miles away from where they started from.

They would have to adjust for about 1600 feet or more of 'curvature', if Earth was a ball.

No, they measure for BOTH level flight AND altitude, with instruments.

The only way we CAN measure for level flight, within air, is measuring the air pressure on the top and the bottom of the plane.

No, that isn't how it works.

If by level flight you mean if they are gaining or losing altitude, that is done with what is effectively a leaky altimeter. Effectively measuring the pressure indicated altitude relative to what it was a short while ago.
Measuring the air pressure at the top and bottom of the plane will not help them.

If Earth was a ball, planes would be flying upward in level flights, which they don't, and prove that Earth is flat, when they land down 2000 miles away from where they started from.

Why?
Stop just asserting delusional BS.
As Earth is round, the air pressure is in roughly spherical layers. So if they fly level, they will remain at the same altitude above mean sea level, which is curved following Earth's curvature.

There is no reason at all to think they would need to magically fly upwards.
The fact that you just assert it is magically upwards without any indication of location or direction or path and so on just further demonstrates your claim is pure BS.
All it takes to show that is to consider the reverse journey.
If your BS was true, then the reverse journey should show that they are flying downwards in level flight.
But according to your claim it would need to show them flying upwards in level flight.
This is a contradiction, showing your claim is BS.

So no, it doesn't prove Earth is flat, it proves you are spouting pure BS.
The fact that this (or very similar points) have already been explained to you shows you are knowingly spouting pure BS, i.e. you are lying to us.

They would have to adjust for about 1600 feet or more of 'curvature', if Earth was a ball.

No, they wouldn't.
If you think they would clearly explain what adjustments you think they would need to make and why.

Quote from: turbonium2 on September 01, 2023, 09:14:08 PM

How could we even MEASURE for a ball Earth's surface, being curved all over the surface below a plane in air?

You only measure for the surface when you are going for a terrain based altitude such as landing.
Most of the time, you don't measure for the surface at all.
Instead, you measure for level.
When a plane flies over a hill, level doesn't magically align to that hill.

True. Level is measured throughout their flights

And we know level is flat and horizontal. It’s absolute fact

When a 6 inch level measures a shelf on a wall as level, it is flat and horizontal

Same as every level measures flat and horizontal


Your imaginary curve would not even BE measurable over 6 inches. 

Using a precise laser level over the same 6 inches would confirm level is flat and horizontal

Lasers point straight outward in air. The made up curved air pressure and made up curved surface of Earth are proven as nonsense at that alone

And we know level is flat and horizontal. It’s absolute fact

No, we don't.
That is a blatant lie you keep on repeating.

When a 6 inch level measures a shelf on a wall as level, it is flat and horizontal

That is NOT a plane.
Care to stick to planes?

Even if you did want to use a 6 inch level, is it really flat? Or does it follow the curvature of Earth?
Because at that scale you are looking at a roughly 6 inch bulge.

In reality, once you put the shelf in, it will sag, likely with that sag being more significant than the curvature over that distance.

Repeating the same pathetic lies will not help you.

Your imaginary curve would not even BE measurable over 6 inches.

You mean the real curve.
And that just further demonstrates your dishonesty, and that this dishonest of yours is entirely intentional.
Over such a short distance you cannot tell if level is following a curve or not.
So using it as an example to claim level is flat is just you wilfully lying to everyone.

Using a precise laser level over the same 6 inches would confirm level is flat and horizontal

No, it wouldn't.

You need a laser accurate to less than 0.5 nm.

Optical lasers are limited by the wavelength of light, making them useless for measurements below a few hundred nm.

The made up curved air pressure and made up curved surface of Earth are proven as nonsense at that alone

Your fantasy proves nothing except your own dishonesty or ignorance.

Now care to address the actual topic?

Again, you have a plane flying from point A to point B. It then stops for a while and takes a return trip.

According to your delusional BS, the plane has to be ascending during this trip, both the trip from A to B and from B to A.
That means in your delusional fantasy, A must be at a greater altitude than itself.

Notice the problem here?

I think there is some confusion here.

Is the OP referring to what an Attitude Indicator provides?  The AI works through a gyro to indicate the aircraft’s attitude relative to the level, i.e. at 90degrees to the direction of the force of gravity. And yes at high altitudes it will show as if the aircraft is pointing straight at the horizon even though the visible horizon will in fact be a few degrees below eye level.

In which case the discussions about Flight level v altitude v height are quite the diversion. Altimeters measure a difference between local air pressure and a datum air pressure (that can be pressure at ground level (height), pressure at sea level (altitude), or 1013.2hPa, or 29.92in (Flight Level)). The latter is what all aircraft will be using above a certain altitude (called the transition altitude, which varies from nation to nation usually depending on terrain). Based on a fixed datum, an aircraft maintaining FL250 could be, at various stages of flight, at altitude 24,000ft at one point, and altitude 26,000ft at another as air pressure varies over the route. The key is that all the other aircraft around it will also be using the same datum, and thus will also be staying in the same band of constant pressure as it rises and falls in altitude.

Quote from: turbonium2 on October 07, 2023, 09:33:16 PM

And we know level is flat and horizontal. It’s absolute fact

No, we don't.
That is a blatant lie you keep on repeating.

Quote from: turbonium2 on October 07, 2023, 09:33:16 PM

When a 6 inch level measures a shelf on a wall as level, it is flat and horizontal

That is NOT a plane.
Care to stick to planes?

Even if you did want to use a 6 inch level, is it really flat? Or does it follow the curvature of Earth?
Because at that scale you are looking at a roughly 6 inch bulge.

In reality, once you put the shelf in, it will sag, likely with that sag being more significant than the curvature over that distance.

Repeating the same pathetic lies will not help you.

Quote from: turbonium2 on October 07, 2023, 09:33:16 PM

Your imaginary curve would not even BE measurable over 6 inches.

You mean the real curve.
And that just further demonstrates your dishonesty, and that this dishonest of yours is entirely intentional.
Over such a short distance you cannot tell if level is following a curve or not.
So using it as an example to claim level is flat is just you wilfully lying to everyone.

Quote from: turbonium2 on October 07, 2023, 10:11:46 PM

Using a precise laser level over the same 6 inches would confirm level is flat and horizontal

No, it wouldn't.

You need a laser accurate to less than 0.5 nm.

Optical lasers are limited by the wavelength of light, making them useless for measurements below a few hundred nm.

Quote from: turbonium2 on October 07, 2023, 10:11:46 PM

The made up curved air pressure and made up curved surface of Earth are proven as nonsense at that alone

Your fantasy proves nothing except your own dishonesty or ignorance.

Now care to address the actual topic?

Again, you have a plane flying from point A to point B. It then stops for a while and takes a return trip.

According to your delusional BS, the plane has to be ascending during this trip, both the trip from A to B and from B to A.
That means in your delusional fantasy, A must be at a greater altitude than itself.

Notice the problem here?

The only problem is your lack of understanding this

Planes do not ascend or descend over their flights when level at altitude. Nor do they need to, nor did I ever say they DID need to. 

You put bs claims on me that I never said. Drop the bs act

Trying to invent some imaginary “curve” that doesn’t exist, cannot be measured or seen at all, is a useless, worthless argument. Why not claim that Earth is shaped as a cone or wedge?  It’s just as good as claiming it’s shaped like a ball

Say that levels measure for a conical surface as “level”, due to a made up force within Earth, and ask me to prove it’s not conical! 

A 6 inch level has a straight edge around it, which is measured straight by instruments

That level can be angled in any direction and will always have straight edges

Your imaginary curve doesn’t exist at all. If there was curvature over Earths surface  levels WOULD HAVE to be curved at the SAME RATE of Earths curvature, no matter how SLIGHT of curve necessary

Planes do not ascend or descend over their flights when level at altitude.

They change altitude by changing power settings and flight surfaces.  For a curved earth and curved gravity equipotential why would you drift up if power settings are trimmed to maintain altitude. 

Flat Earth Follies: Planes would have to constantly pitch down to fly!
Flat Earth Claim

Planes would have to constantly pitch down to fly!


Short Version

In the Globe model "LEVEL" follows a sphere of uniform gravity potential. Feel free to disprove that is the case if you can but that is the model.


https://flatearthinsanity.blogspot.com/2016/09/flat-earth-follies-planes-would-have-to.html?m=1

The Elevator does not directly control the Pitch of the Airplane - it controls the RATE OF PITCH.

I think that Flat Earthers don't understand this concept.

To maintain level flight the pilot must find BOTH the elevator trim and power setting which maintains a constant altitude - they mostly use the Vertical Speed indicator to make fine adjustments to elevator trim to find the constant pitch rate that keeps Vertical Speed near zero and then makes POWER SETTING adjustments as needed to hold that Vertical Speed with a fairly constant airspeed.   If you want a higher airspeed you need to both increase power AND adjust the elevator trim so the pitch rate matches OR ELSE YOU WILL START CLIMBING.

This is a fact, I have personally flown small planes and they teach you about power control pretty much from Day #1.  You climb & descent mostly by changing the power setting (which changes when you make other configuration changes such as increasing flaps).

Now, how is a pilot supposed to tell that a TINY fraction of the elevator trim has to do with the curvature rate as opposed to all of the other forces acting on the airplane? They couldn't possibly.

A curved gravity equipotential presents ABSOLUTELY ZERO issues for an airplane in flight.

So YES, the PLANE is (technically) constantly pitching forward as it flies the curvature of the Earth.  But it doesn't feel like pitch because DOWN is changing at the same time and it's an incredibly slight rate of pitch overwhelmed by other dynamic forces acting on the aircraft.

[
A 6 inch level has a straight edge around it, which is measured straight by instruments

Meaning what in what context?  When the surveyor’s definition of level surface is something like “In the Globe model "LEVEL" follows a sphere of uniform gravity potential.”



Anyway….

Quote from: turbonium2 on July 02, 2023, 03:36:18 AM

If the Earth curved down 3 miles away, it would CERTAINLY be significant, and would have been MEASURED as such.

Used this in another thread..

Like this?

Quote from: bulmabriefs144 on June 21, 2023, 08:49:25 PM

A sphere is by definition three-dimensional. A ball can't be flat.

You really have no concept of how big the earth is to an individual’s frame of reference.


Just like this large tank and using this small straight edge on this level as a frame of reference.



Looks flat with a small frame of reference?

But the tank is clearly curved.






What should the curve look like to a person 6 foot tall for an earth 30,000 times, or more, greater in diameter than the tank?



https://flatearth.ws/horizon-dip

The only problem is your lack of understanding this

No, the problem is your repeated dishonesty and your pathetic attempts to lie about the RE; including fleeing from trivial questions.

Planes do not ascend or descend over their flights when level at altitude. Nor do they need to, nor did I ever say they DID need to.

You claimed they needed to on a RE.
You may not have said those exact words, but that is the gist of your claim.

Here is it again:

If Earth was a ball, planes would be flying upward in level flights, which they don't, and prove that Earth is flat, when they land down 2000 miles away from where they started from.

Don't try to blatantly lie about what you have said, to pretend you never said such delusional BS to pretend you are wrong.
It just further demonstrates your dishonesty and how pathetic your position is.

Why not try to grow a spine and admit you were wrong, and that your strawman of the RE model isn't correct?

Trying to invent some imaginary “curve” that doesn’t exist, cannot be measured or seen at all, is a useless, worthless argument.

So why do you keep doing it?
Why not stick to the real curve, which does exist, which is seen, which can be measured?

A 6 inch level has a straight edge around it, which is measured straight by instruments

To what level of accuracy/precision?
To the sub nm level precision you need to claim it is straight rather than following Earth's curve?

All edges have some tolerance.

Your imaginary curve doesn’t exist at all.

Your imaginary curve doesn't exist. The real curve of Earth does.

If there was curvature over Earths surface  levels WOULD HAVE to be curved at the SAME RATE of Earths curvature, no matter how SLIGHT of curve necessary

Why?
You have already answered why that is pure BS.
If that curve is too slight to make any significant difference, why would they need to be?

But how do you know they aren't?
Due to how slight it is, they would match that curve to a comparable level of precision as matching a straight line. Depending on the exact straight edge you are comparing, it could go either way, being closer to one or the other.

On multiple places on the Flat-Earth Wiki, it is being stated that the horizon is always at your eye level:

Quote from: https://theflatearthsociety.org/tiki/tiki-index.php?page=Basic+Perspective

A fact of basic perspective is that the line of the horizon is always at eye level with the observer.

If that's true, why can't pilots tell whether an airplane is parallel to the ground simply by looking where the horizon is? Why can't they simply make sure that the horizon is at the eye level?
An obvious answer seems to be that it won't work because the Earth is round and, at the 9'000 meters height (where some airplanes fly), the horizon is visibly below your eye level, 3.14 degrees below your eye level. Trying to align a high-flying airplane assuming the horizon is always at your eye level will crash an airplane.

  and pouring rain.

Quote from: turbonium2 on October 08, 2023, 07:59:35 PM

The only problem is your lack of understanding this

No, the problem is your repeated dishonesty and your pathetic attempts to lie about the RE; including fleeing from trivial questions.

Quote from: turbonium2 on October 08, 2023, 07:59:35 PM

Planes do not ascend or descend over their flights when level at altitude. Nor do they need to, nor did I ever say they DID need to.

You claimed they needed to on a RE.
You may not have said those exact words, but that is the gist of your claim.

Here is it again:

Quote from: turbonium2 on September 17, 2023, 02:27:35 AM

If Earth was a ball, planes would be flying upward in level flights, which they don't, and prove that Earth is flat, when they land down 2000 miles away from where they started from.

Don't try to blatantly lie about what you have said, to pretend you never said such delusional BS to pretend you are wrong.
It just further demonstrates your dishonesty and how pathetic your position is.

Why not try to grow a spine and admit you were wrong, and that your strawman of the RE model isn't correct?

Quote from: turbonium2 on October 08, 2023, 07:59:35 PM

Trying to invent some imaginary “curve” that doesn’t exist, cannot be measured or seen at all, is a useless, worthless argument.

So why do you keep doing it?
Why not stick to the real curve, which does exist, which is seen, which can be measured?

Quote from: turbonium2 on October 08, 2023, 07:59:35 PM

A 6 inch level has a straight edge around it, which is measured straight by instruments

To what level of accuracy/precision?
To the sub nm level precision you need to claim it is straight rather than following Earth's curve?

All edges have some tolerance.

Quote from: turbonium2 on October 08, 2023, 07:59:35 PM

Your imaginary curve doesn’t exist at all.

Your imaginary curve doesn't exist. The real curve of Earth does.

Quote from: turbonium2 on October 08, 2023, 07:59:35 PM

If there was curvature over Earths surface  levels WOULD HAVE to be curved at the SAME RATE of Earths curvature, no matter how SLIGHT of curve necessary

Why?
You have already answered why that is pure BS.
If that curve is too slight to make any significant difference, why would they need to be?

But how do you know they aren't?
Due to how slight it is, they would match that curve to a comparable level of precision as matching a straight line. Depending on the exact straight edge you are comparing, it could go either way, being closer to one or the other.

The slightness of curve on the surface over a mile of distance when a flight spans thousands of miles over the surface, would make every inch of curve important and accounted for in flights

The slightness of curve on the surface over a mile of distance when a flight spans thousands of miles over the surface, would make every inch of curve important and accounted for in flights

Repeating the same delusional BS wont help you.

Likewise, fleeing from your lies after it has been shown how insane they are wont help you.

Again, this was your claim:

If Earth was a ball, planes would be flying upward in level flights, which they don't, and prove that Earth is flat, when they land down 2000 miles away from where they started from.

Logically this means if a plane flies from A to B, flying level, on a RE you are claiming that B must be above A.
And if that plane then flies back from B to A, then A must be above B.
That means A must be above B which must be above A, so A must be above itself.

This shows your claim is pure BS.

A plane flying level over a RE does NOT need to be going upwards.

Going to be honest for once and admit you were wrong?

Or considering you want to flee from that yet again, and spout the same old garbage of "planes would need to account for curvature"; then how about you tell us exactly HOW the planes would need to do that.
Tell us exactly what the pilots/planes would need to do and why.
If you can't, then stop lying by claiming they need to account for it.

Again, when a plane is flying level, pilots already need to adjust for the plane not being ideal. That means they need to control pitch, trimming it forwards or backwards to ensure level flight.
A plane flying at 1000 km/hr would need to adjust 0.0025 degrees per second. That is basically nothing.
The ABSOLUTELY TINY amount they would need to do to compensate for curvature would already be taken care of just for keeping the plane level.
Otherwise, they would need to account for every motion of every passenger on board the plane and constantly adjust specifically for that.

The slightness of curve on the surface over a mile of distance when a flight spans thousands of miles over the surface, would make every inch of curve important and accounted for in flights

Why?

Again….

Now, how is a pilot supposed to tell that a TINY fraction of the elevator trim has to do with the curvature rate as opposed to all of the other forces acting on the airplane? They couldn't possibly.

A curved gravity equipotential presents ABSOLUTELY ZERO issues for an airplane in flight.

So YES, the PLANE is (technically) constantly pitching forward as it flies the curvature of the Earth.  But it doesn't feel like pitch because DOWN is changing at the same time and it's an incredibly slight rate of pitch overwhelmed by other dynamic forces acting on the aircraft.


https://flatearthinsanity.blogspot.com/2016/09/flat-earth-follies-planes-would-have-to.html?m=1

Flying in any direction but level is measured by their instruments at all times, when it occurs, and is corrected for, adjusted for, afterwards, to return to level flight again.

We all recognize what level flight means, what direction it is going in.

How would you even IDENTIFY or MEASURE for any sort of ‘curve’ that is so ‘slight’ over such a small distance, that will repeat over and over countless times during a flight of thousands of miles long?

When a plane flies at 500 mph through a flight, it measures for level flight throughout the time. If level was measured for a ‘curve’ during flights, it might be 1/32 of an inch, or a few mm, yet it would HAVE to be measured in planes, if there WAS any ‘curve’ to Earths surface, as you claim there is.

That plane would go over 3-4 inches of ‘curvature’ per minute of flight, or more, and you would claim we ‘don’t need to account for it’ in flights!!??

What about a jet going twice that speed, going over twice that ‘curvature’?  Still no need to account for ‘curvature’?

Level means flat, straight and horizontal in direction, nothing of a curve at all.