It is the one with the white dot on it (mine has the word RATE written across it).

I just set the Dukes at my final anticipated Flight Level -2500 feet when I start up(I know I said 2000 in my email, but -2500 gets me a tad over the 5.5 psi and seems to work well) and, unless the destination airport is higher than the Airport ALT reading, I just leave it there for the duration of the flight.  Make sure you set it as soon as possible (you can even do it prior to power up) to give it time to adjust the pressure head – it is a very slow process. 

Lowering the FL on the Dukes once I am at the flight level might result in an increase in pressurization for a short period when the system is going toward max pressure, then a decline when finally descending below the Airport ALT, IMHO a more uncomfortable progression pressure wise than just leaving it alone.  If ATC steps me down 5,000 feet or so and I notice the Dukes is still at a higher ALT, I will reset it to my destination elevation plus 3000 feet, but usually I just leave the Dukes where it is and all is fine.

Pete

From: Dico Reijers [mailto:dico@internetworks.ca]

Hi Pete,

Thanks for your detailed email.   I have a couple questions...

1) which is the rate knob?  The only knob with any description on it is the one where I set the altitude.  There is another knob beside it, however it doesn't have a label on it (see attached photo). 

2)  If I am FL200 and my destination airport is still 150nm away... at what point would I turn the pressurization to the field elevation?  As soon as I start my decent?

Thanks,

-dr