OK.. MSL it is......But.......

There's a lot more to the story!

Funny thing, where is REALLY matters, (collision avoidance) MSL is not
used.........such as transponders, PCAS etc.....they use pressure alt,
as does IFR flight above 18,000. Also flight recorders use pressure
alt. Acrobatic pilots tend to use alt setting zero, since they want
to know exactly where the ground is without doing math.

Of course all the "experts" say that glider landing, especially off
field landing, MUST be done by "visual reference to the ground" not by
altimeter at all.

Then there's

Absolute altitude
Calibrated altitude
Radar altitude
GPS altitude
All that "Q" stuff
Field elevation
So called, (but incorrectly) AGL (really should be "above starting
point" as the ground varies as soon as you move!)
Non standard pressure lapse rates
Flight for high to low pressure, flight from hot to cold, etc
Mean sea level
Altimeter error....(anybody know how much error is allowed?)(anybody
ever go around te airport and note the differences from one altimetier
to the other?)

Sensitive altimeter, non sensitive altimeter?

Then how about "metric" altimiters? 300 meters per revolution
How about altimeters with the "zero" on the bottom

So.... I trust that all you instructors teach all of this and more to
your first-lesson students....don't leave ANYTHING out... law of
primacy and all that.....

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