Altitude Density - is it modelled

[Guest Twister]

I guess we can conclude this issue by saying that Density Altitude is reasonably well modelled in FS2K2.Nice to know.Cheers.Twister

[Avcomware 1]

Hi. I just wanted to make sure that we are all on the same page, and there is no miss understanding, since this applies to

[LAdamson 240]

Be sure to catch the latest edition of FLYING magazine. A lenthly article regarding the use of mixtures & CFI's........L.Adamson

[Guest]

Very nice article, avcomware, I'm sure . I just wanted to add a little comment on shooting the approaches without resetting the altimeter. Of course it's a huge mistake not to reset the altimeter with the local or if none is available the regional setting (by FSS), which leads to a difference of several hundreds of feet in your example. But there is another thing that almost nobody does : correcting the published minimas for the non-standard temperature. Imagine making an approach into a highly elevated aerodrome where the temperature is way colder than the standard temp for that pressure altitude. The altimeter will "over-read" because it's simply measuring pressure. You will however be much lower than you think, because the air being colder hence denser will be more "compact". The result is that pressure will diminish quicker with vertical distance than if the air would have been at standard density, thereby "compressing" the vertical scale of pressure altitudes. Not correcting the minimas in this case also leads to differences enough to make you hit the ground when reaching the minimums (MDA/DA). If you take an ILS approach CAT-I with a typical DH of 200 feet, and the airport is at 2500 feet of elevation, with a big enough deviation those 200 feet can easily be brought down to the terrain level ! The same applies for the glideslope check altitude at the outer marker. The published value must be corrected for non-standard temp otherwise one might think he's on a false glideslope signal. Of course, this doesn't apply to CAT-II & III approaches which use the Radio Altimeter instead of the baro altimeter to determine the minimums. Tables to correct for those deviations exist, and in fact correction is only significant from certain amount of deviation from standard atmosphere. Now actually all this is only used where the deviation is big enough to be significant. No need to correct for 10