Mode C Altitude Q - no Kalisman Correction? (Barometric Pressuredeviation correction?)

True. The equipment at the controllers' end corrects for barometric
pressure fluctuations, so the info the controller sees is pretty accurate.

In our neck of the woods (NZ) they only apply a correction below the
transition altitude - no need for any correction for flight levels.

Assume it's the same in the states

"Cockpit Colin" wrote in message
...

In our neck of the woods (NZ) they only apply a correction below the
transition altitude - no need for any correction for flight levels.

Assume it's the same in the states


It's the same everywhere. It can be no other way.

Steven P. McNicoll wrote:

It's the same everywhere. It can be no other way.

Of course it could. Whether it would make sense is a different question.

Stefan

"Stefan" wrote in message
...

Of course it could. Whether it would make sense is a different question.


How could it be any other way?

Steven P. McNicoll wrote:

How could it be any other way?

Just a few examples: It could be QNH everywhere (requires defined QNH
regions). It could be GPS altitude (would even simplify things a lot,
but requires all aircraft to be expensively equipped). Heck, it could
even be radar altitude everywhere, of course compensated for ground
elevation. As I said, whether it would make sense or even be practical
is a different question, but there are a lot of solutions which are
thinkable.

Stefan

"Stefan" wrote in message
...

Just a few examples: It could be QNH everywhere (requires defined QNH
regions).


If it's QNH everywhere there's no transition altitude.



It could be GPS altitude (would even simplify things a lot, but requires
all aircraft to be expensively equipped). Heck, it could even be radar
altitude everywhere, of course compensated for ground elevation. As I
said, whether it would make sense or even be practical is a different
question, but there are a lot of solutions which are thinkable.


How does one set the barometric pressure for GPS altitude or radar altitude?

Steven P. McNicoll wrote:

If it's QNH everywhere there's no transition altitude.
....

Right.

As I understood, you said: This is the only way to set the altimeter. I
answered: No, there are a myriade of ways to do it, from which one was
chosen, probably for good reasons.

Maybe I misunderstood your first statement.

Stefan