On Oct 27, 7:47*pm, Bruce Hoult wrote:
On Oct 28, 3:13*am, Andy wrote:

For the circling over the airport problem you can get some indication
of altitude by looking at the path the wingtip traces on the ground
from a known bank angle. *Above a certain height the path will be
counter to the turning direction, below that height it will be in the
same direction. Do the math to convince yourself.

I guess you didn't do the math yourself :-)

The height at which the change from wingtip-goes-backwards to wingtip-
goes-forwards occurs is too low to be used for normal circuit entry.
At 40 knots it's only 140 ft, and at 60 knots it is about 320 ft. If
you want to use this to judge a 700 ft circuit entry then you'll have
to be flying at 90 knots.

Glad you mentioned this. I did think of this myself also, and tried it
on a simulator many many times before reading these posts and in every
case the wingtip appeared to move backwards over the terrain. Decided
it would not work.