Bob the Unbeliever
Well-Known Member
I am not sure of the need of an altitude adjustment. The force of gravity is perpendicular to a plane and will keep it at the same level. And also, just as cars do not drive perfectly straight, a plane does not fly perfectly level. Even if there were adjustments for such a curve they would be smaller than adjustments for changes in updrafts, and continual human error in flight.
When you are at altitude? There are fewer and fewer updrafts, especially if you fly well above the cloud cover. Yes, there are high altitude jetstreams and such.
And yes-- gravity does have an effect-- but an engine driven airplane (not a sailplane or glider) tends to push thorough most of these, assuming you are not in a major storm front or other severe weather. I should have mentioned that. And really, gravity is the weakest of all the nuclear forces, is it not? The subtle difference between the gravitational pull at 10,000 feet, as compared to 15,000 feet? I doubt you could measure it without some very sophisticated equipment on board--likely heavier than the airplane.
But, 5,000 feet can make a visible difference to an observer in the plane....
My airplane trip was in 100% clear weather, with near complete lack of any clouds even. We had a mild cross wind that needed constant fighting (the plane had no real autopilot), and was tiring for the pilot.
But he loved talking about flying, and had observed the need to constantly correct the altitude, especially if there was no weather.