Mxsmanic wrote:

Nomen Nescio writes:

One thing you keep missing as a "pretend" pilot is that an error of
+/- 100 ft is insignificant in the real world.

GPS errors can easily exceed 100 feet. And 100 feet sounds pretty
significant for RVSM. With errors that large, some aircraft may be
vertically separated by only slight more than the spans of their
wings.

The equipment requirements for RVSM are certainly far more stringent
than what a VFR pilot needs and who might have to use GPS altitude as
a data source under some hypothetical situation.

Ron Lee