In article , Henry Kisor wrote:
All:

Can a 172 flying at 200 feet above water across Lake Superior get through
undetected by radar or AWACS? Are there holes in radar coverage?

It depends.

As a point of data, our local airport's radar (Ronaldsway, EGNS) can
see shipping in the Irish Sea quite clearly. There are especially big
primary returns on the larger vessels like the Sea Cat (a large
vehicle-carrying catamaran). However, the local geography (a mountain)
means that to the north of the island, their radar can't see anything
below about 3000' AGL (and indeed you have no radio contact either
in that area).

IIRC, that part of North America is fairly flat so radar will be able to
see very low. As for non-metallic aircraft, when I was flying in Houston
under IFR once, I was advised of a slow moving primary target, which
turned out to be a flock of geese.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"