terry wrote:
Are you saying I should just
simply substitute the declared density altitude for the pressure
altitude on the climb wt limit graph?


Yes.
That is EXACTLY what I am saying. Calculated is better than declared,
but if on field or regional weather is not available use what you have.
(sorry, I presumed US flying here, not aussie back country)

If your density altitude is X, your performance is always Y
(oversimplified).

A hot day on the coast may have the same density alt as a cold day in
the hills. If Density Alt is X, your performance will always be that
same Y.

Your performance at a density altitude of 4000 feet for example, on a
standard day (which also equals the pressure altitude chart, by
definition)..... is THE SAME at a density altitude of 4000 feet on a hot
day (presumably somewhere else, but dont let that confuse the issue).

All the plane cares about is that its a density alt of 4000 ft. Whether
its a standard day 4000 feet density alt or a hot day or a cold day or a
high pressure day or a low pressure day it does not matter. If your
CALCULATED density altitude is 4000 feet, your airplane will behave as
if it was at 4000 feet on a standard temp/pressure day. So you use the
chart for 4000 ft pressure altitude (which on a standard day, is 4000
feet density altitude).



As for the bezel ring comment, in the states, most of the rental planes
I've used have a little plastic ring on the airspeed indicator. I had a
momentary brain fart... that ring is used to calculate a rough true
airspeed. Not all ASI's have it. Sorry for the bad info.