Airplanes Landing & Altitude Problem

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    Airplanes Altitude
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Discussion Overview

The discussion revolves around the mechanics of airplane landing in relation to the Earth's rotation and altitude. Participants explore how an airplane maintains its trajectory and speed relative to the Earth's surface during ascent and descent, particularly focusing on the implications of the Earth's eastward spin at different altitudes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how an airplane must adjust its eastward velocity as it ascends to 10,000 feet to remain aligned with the Earth's surface during landing.
  • Another participant suggests that, at normal altitudes, the atmosphere moves with the Earth's surface, implying that a plane can maintain its heading without needing to account for the Earth's rotation significantly.
  • A participant calculates that at 10,000 feet, an airplane would need to travel slightly faster than the surface speed of the Earth to maintain its position over a runway, estimating this speed difference to be about ½ mile per hour at the equator.
  • There is a correction made regarding the speed difference, with a later post clarifying the calculation to approximately ¼ mile per hour, which is described as slower than a walking pace.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the impact of the Earth's rotation on airplane speed and trajectory. While some agree on the general mechanics of flight and atmospheric movement, there is no consensus on the exact implications of altitude and speed adjustments needed for landing.

Contextual Notes

Discussions include assumptions about the uniformity of atmospheric movement with the Earth's surface and the specific calculations regarding speed adjustments at altitude, which may depend on various factors such as location and wind conditions.

GilGiy
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First I'm going to say that I was supposed to select a prefix for this thread... I'm not sure what that's for so my apologies if I did it wrong.

So here's a problem that I was presented with a bit ago (by a flat earther[emoji849][emoji19][emoji44]) and I'm sort of confused. It's been about a year since I took physics but I don't think that's a good excuse.

Let's say an airplane takes off from New York and flies to an Airport directly south, both runways run North and South. Also, the Earth is spinning directly East.

As the plane takes off, it will be traveling East at the same speed of the Earth. However, as it climbs to 10,000 feet it must start traveling much faster to the east to stay caught up with the earth, correct?

Say it is then flying at 10,000' but must land. It is traveling East at the rate of the surface of the Earth plus X m/s to stay traveling in a straight line above the Earth's surface. As it descends to land, how does it stay lined up with the runway? Will it not still be traveling at X m/s relative to the surface of the Earth when it reaches the runway? What does the pilot do with that extra sideways velocity?

If the question itself is confusing that's cause I'm confused... Here's the video that got my wheels turning:

Thanks in advance!
Gilbert
 
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Welcome to the PF. :smile:.

To a first approximation, at normal plane altitudes, the atmosphere moves with the surface of the Earth (before you account for whatever direction the wind is blowing that day).

Just stay on your compass heading toward the destination airport, and you should be fine.
 
GilGiy said:
However, as it climbs to 10,000 feet it must start traveling much faster to the east to stay caught up with the earth, correct?
The Earth does not spin very rapidly. Just a tad more than one rotation in 24 hours. At the equator, that amounts to a respectable 1000 miles per hour eastward. 10,000 feet (about two miles) above the equator, would need an extra 2 miles radius times 2π = 6 miles circumference traveled eastward in 24 hours to keep up. About ½ of a mile per hour faster than the surface of the Earth below. Slower than a walking pace.

Edit: Corrected ¼ to ½
 
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jbriggs444 said:
The Earth does not spin very rapidly. Just a tad more than one rotation in 24 hours. At the equator, that amounts to a respectable 1000 miles per hour eastward. 10,000 feet (about two miles) above the equator, that amounts to an extra 2 miles times 2π = 6 miles circumference traveled in 24 hours -- approximately an extra ¼ of a mile per hour eastward. That's slower than a walking pace.
Awesome that makes perfect sense, thanks!
 

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