"Peter Duniho" wrote in message ...
"Robert Moore" wrote in message
. 6...
(Malcolm Teas) wrote

Think about density altitude. At -20 C and sea level, the density alt
is just under -10000 feet according to the my trust E6B. At -40 C and
9000 feet pressure alt, the density alt is -10000 feet.


Better get a new E6B. :-)

Or, perhaps, remember how to do density alt. calculations. Yep, I
messed up there.

He got the wrong numbers, but it IS true that the density altitude winds up
about the same for both calculations (around -5000'). So maybe the answer
IS something that has to do with density altitude.

Well I get a density alt of about -5000 for sea level and -20 C, and
5000 for 9000 foot press. alt and -40 C. This is with my revised E6B.
grin So, 4000 to 5000 less than the pressure altitude at least.

-Malcolm Teas