On Wed, 13 Jul 2005 16:02:20 -0400, "Peter R."
wrote:

"Peter R." wrote:

Assuming we're talking about KUDD, 73' elevation, 40 deg C temp,
altimeter 29.79, I come up with pressure altitude of 190' and density
alt of 3050.

Hmmm, I keep arriving at a DA about 1200 feet higher. Cross checking this
with several DA calculator websites confirms about 4,200 ft or so.

Nevermind, I see the discrepancy. The OP was asking about 120 degrees F,
which is about 49 degrees C. That was the temp I was using.

Yea, my bad. They only print the chart to 40 so that number got stuck
in my head. 49C comes out with 4k density alt. So extrapolating from
the 40C column at 4K comes out with 1770/3085 for roll/50' obst.