[ACE-OF-ACES]

Originally Posted by klem

OK, well there is the parameter I_AmbientTemp.

Ah yes, I forgot about that one!

I just don't recall if every plane had one? I noticed that when a plane does not have a guage for a said "I" value that said value is not aval to read/log.

But we can use that value and log it along with the "Z" value (which is allways active) you were using to see if they are the same, or if they diverage at some point (alt). If they don't than I was worring for nuttin and we can continue to use the "Z" value.

Originally Posted by klem

I have two questions.

Ok lets see if I have two answers!

Originally Posted by klem

1. TLR is a rate so presumably below the Tropopause the Temperature Lapse is - Alt_Ind x TLR but above the Tropopause the Temperature Lapse is simply 56.5C ?

Exactally!

Take a look at any standard atmosphere table/graph and you will see that is indeed the case

Originally Posted by klem

and similarly......
2. Within the DA calc, T_Std/TLR would appear to calculate an altitude. Does it hold good above the Tropopause where the lapse rate is zero or should I be capping T_Std at 288.15 - 56.5 = 231.65K once T_Std/TLR hits 56.5?

EDIT: Sorry, ref Q.2, I meant should I replace T_Std/TLR with some other expression above the Tropopause??

EDIT2: Think I've got it

if ( 15 - Pressure_Alt_ft*0.0019812 < -56.5)
{
TropAlt = PressureAlt - 56.5/0.0019812
TempStd = 288.15 - 56.5;
Density_Alt_ft = Pressure_Alt_ft + (TempStd/0.0019812 + TropAlt) * (1 - Math.Pow((TempStd / I_AmbientAirTemperature),0.2349690));
else
TempLapse= Pressure_Alt_ft*0.0019812;
TempStd = 288.15 - Templapse;
Density_Alt_ft = Pressure_Alt_ft + (TempStd/0.0019812) * (1 - Math.Pow((TempStd / I_AmbientAirTemperature),0.2349690));
}
TempStd = 288.15 - TempLapse;
Density_Alt_ft = Pressure_Alt_ft + (TempStd/0.0019812) * (1 - Math.Pow((TempStd / I_AmbientAirTemperature),0.2349690));

Let me look at your code a bit.. and ill get back to ya!

So, one answer, one pending!