You do not take in account the principles of conservation of energy which is transfered to the airplane.
As such, when loosing altitude, the AP gains speed, still most electronic devices show no change in speed, because it's not relative speed, but absolute speed regarding the stationnary universe. This is why a correction must be used with the pressure coefficient formula Cp = dP/(ρ v2 /2) .
However, you stayed strangely quiet on the fact that Google Earth is a video game. Do you trust computer softwares that much?
They can have many flaws too...