Many flat-earthers somehow seem to think that this is such a great "gotcha" question that proves their flat Earth delusion, and which they often present in debates:
"Do airplanes need to constantly pitch their nose down to follow the curve of the Earth?"
And the answer to that question is a big fat
YES!
Yes, yes, yes, yes, a thousand times YES! Yes they do! That is the only correct answer. There are no "buts".
By this point I'm getting sick and tired of the vast majority of debunkers and, incredibly, even some airplane pilots answering something other then a clear unambiguous "yes". Astonishingly, and sadly, some of them, sometimes even some airplane pilots, outright answer with "no", which is just mind-boggling, and goes to show that even experienced professional airline pilots don't know every single detail about their own profession and specialty, even though they really should.
I'll explain why I think that misconception is happening, sometimes even among pilots, but first let me explain in more detail why the answer is a clear and unambiguous "yes":
When an airplane is flying somewhere, for most of the trip it has to maintain a particular altitude (rather obviously for practical flight-mechanical reasons, but also because of air traffic safety. Most airplanes are outright instructed by air traffic control to use and maintain a particular altitude.)
Rather obviously, because of air currents, winds, differences in air pressure and myriads of other reasons, if nothing is done, they tend to start veering up or down. In the vast majority of situations the autopilot makes small corrections to compensate for this and maintain a constant altitude. It does this by so-called "trimming", ie. adjusting the trim ailerons, which make the airplane pitch up or down, and automatically maintain that pitch position. (If, for example, the airplane is constantly pitching up, the trim ailerons are adjusted so that they apply a constant pitch-down force to compensate, and vice-versa.)
In fact, trim ailerons (or as they are more technically called, "trim tabs") are absolutely crucial for an airplane to be stable. Without them, airplanes would be very unwieldy and hard to control because any atmospheric, air pressure, temperature, air humidity, or any of the myriads of other physical reasons would cause the airplane to veer up or down, or even to the side, requiring constant corrections with the airplane's yoke. The trim ailerons allow setting a constant pitch or yaw force to compensate for and eliminate such instabilities. Curiously, most people don't actually know that airplanes are controlled probably 99% of the time with the trim ailerons, not the main control surfaces (that are operated with the yoke). For example, if the airplane needs to ascend or descend to another altitude, this is usually told to the autopilot, which then usually uses the trim ailerons to do so (unless the ascent or descent needs to be very rapid.)
And the thing is, even if the autopilot were not usable for some reason, and the pilot would need to control the plane manually, he would do it exactly like the autopilot does: In other words, if the airplane seems to be veering up or down, he would adjust the trim to compensate, to once again regain a level flight which maintains the desired altitude. (And this was indeed the case before autopilots existed.)
And yes: As a side effect of this, airplanes do constantly pitch their noses down as they fly along the curved Earth surface. Sure, this downwards pitch is extremely slow and subtle (because the Earth is so enormously big and thus the curvature is minuscule), but it is a non-zero downwards constant pitch. This is indeed required to maintain a constant altitude from sea level.
It's just that this is more like a "side-effect" that's hidden behind the major reasons why trim ailerons are being used and constantly adjusted. By far the primary and major reason is, of course, and as mentioned, that differences in air pressure, air currents and a myriad of other reasons tend to affect the altitude and pitch of the plane, so the trim ailerons are adjusted to compensate. But as a "hidden" side-effect this also causes the airplane to follow the curve of the Earth. The downwards pitch that this requires is so subtle as to be imperceptible, but it does exist.
Most airplanes, particularly passenger planes and other large aircraft, have an inertial navigation system installed. In airplanes this is a backup navigation system to support the other ones, and even work as the primary navigation system in the extreme case that all the other systems were to fail.
What's very peculiar about these inertial navigation systems is that they are completely isolated and enclosed, and do not need to communicate with the outside world, or necessarily even with any of the airplane's other instruments. They calculate the location (and altitude) of the airplane by measuring how the airplane accelerates, decelerates and rotates, with extreme accuracy. They are so sensitive that they can detect even the tiniest changes in speed, direction or orientation, just by measuring acceleration using very precise accelerometers and gyroscopes.
And yes, these systems do detect the airplane pitching down along the curvature of the Earth. This is, in fact, one of the things that the software in these systems needs to compensate for, in order to calculate where the airplane is on Earth.
So, once again: Yes, the airplane is constantly pitching downwards as it flies, and the INS systems do detect it, and have to compensate for it.
So I once again repeat: The answer to the original question is an unambiguous and clear "YES", no question about it, no "buts".
So why do so many people, sometimes even outright professional airline pilots, often give the wrong answer to this question?
What I believe is happening is, primarily, a confusion in terminology and concepts.
You see, when most people, including even some pilots, hear the term "pitch down", what they visualize in their heads is the pilot pushing forward on the yoke in order to make the plane do so. And, thus, when they are asked "does the airplane need to be constantly pitching down", they are incorrectly interpreting that as "does the pilot need to be constantly pushing the yoke forwards?"
Those two things are not the same thing because, as mentioned, that's not the only (or even the primary!) way in which airplanes can pitch. The main way they use is trim ailerons, which are controlled separately from the yoke, and in most situations are adjusted automatically by the autopilot.
It's absolutely detrimental that so many debunkers and, sadly, even some professional pilots, get confused by the question and give the wrong answer. "Pitch down" does not mean "pilot pushes the yoke forward". It means the airplane changing its orientation. Which, in this case, happens primarily by trimming. (It obviously can also be done with the yoke, but that's not how it's usually done.)
I wish people stopped answering that question with anything other than "yes". But alas, even smart experienced people can be stupid and uninformed sometimes.
Comments
Post a Comment