Can anyone tell me what that weird sound is that appears in this video
at 0:03 and lasts until 0:07, and in this other video
from 1:25 until 1:28?
I mean that continuing beep that lasts for several seconds while steadily increasing in pitch until it suddenly stops. Since it typically appears just before touchdown, I always thought it had something to do with the height of the plane. But in the first video it appears very far from touchdown, so that can't be the case (unless it's a malfunction). Does it have to do something with the plane's speed?