Lomcevak,
Aircraft have inertia (which is referenced to the earth and not the airmass in which an aircraft flies)
This is wrong. Inertia is actually referenced to the airmass through which the aircraft was flying a moment ago. In the case of straight flight, this is equivalent to referencing it to the earth - and in fact it is more convenient (and so more common) to do so when describing how windshear works. But when talking about a turning aircraft, it is wrong.
Think about it: Why should inertia be referenced to the surface of the earth? Remember that the earth is spinning around, constantly, very very fast. And it's moving through space even faster. And it's orbiting the sun. And science just happens to pick some random surface a few thousand feet away from our aircraft, which happens to be describing a very complex shape through space, to reference inertia to? Sounds unlikely to me.
What actually happens is that a body's momentum is measured relative to space. But when a body is on the earth, or flying in an airmass, there are all kinds of other effects on that body, such as gravity from the earth and the sun, reactions from other bodies, and so on, which we conveniently ignore - and doing so allows us to assume that momentum is relative to the earth, or the airmass, or whatever - which the body's velocity was measured against a moment ago.
FFF
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