GPS Altitude with WAAS

"G.R. Patterson III" writes:

It's pretty simple, really. It doesn't matter at all if your
altimeter is off by hundreds of feet at cruise altitude if everybody
else at that altitude has the same error.

Unless you're trying to clear mountains using an altimeter setting
from a low-elevation field.

It would be possibly unsafe for you to set your altimeter accurately
when everyone else is setting it to the broadcast local altimeter
setting.

Absolutely -- no one is suggesting changing the altimeter setting.
You just have to be aware of how inaccurate the altimeter is when
obstacle clearance might be an issue. For example, if you are
planning to clear a ridge by only 1000 ft in the winter, you might
want to think again.


All the best,


David