Altitude? What altitude?

[LuckyBlundy]

With the help from this board I finally got magnetic variation straightened out. Now, after rummaging through various websites I have totally confused myself about altitude.

When FS says your altimeter setting is wrong, you correct by hitting the b key. Am I correct in thinking that is now the Indicated Altitude?

When I then adjust the barometer to read 29.92" am I correct in thinking that this is the Pressure Altitude?

Am I also correct in thinking that, for FS, the Calibrated Airspeed is the Indicated Airspeed? In other words, FS has "perfect" instruments that do not need calibration?

The reason I'm doing this is to program my hp50g calculator to do all this and then attempt to try my hand at DED reckoning with the old propliners. Let's say from Honolulu to Melbourne. I'll probably wind up in Calcutta, or maybe Nome but I'd like to try.

[lnuss]

You're right on all counts, with a caveat -- to the best of my knowledge FS has "perfect instruments" but in the real world there are very decided differences in the two airspeeds you mention (CAS and IAS), especially on the lower end of the speed scale. Also, the "b" key just sets to the current altimeter setting -- just to clarify for any who might not understand that.

[rickattfield]

If FS says your altimeter setting is wrong, it means the pressure setting on your altimeter is wrong. If you press 'B', FS will automatically set it to the current pressure setting. If you then adjust it manually, you will be un-setting the correct pressure. That make sense? 29.92 is the standard pressure setting. It's used for flying at a flight level. If instructed to fly at a flight level, always ensure your altimeter is set to 29.92Hg (or 1013mb), if flying at an Altitude, you use the pressure as said in the ATIS (or regional report if you have that information available)

[lnuss]

29.92 is the standard pressure setting. It's used for flying at a flight level.

It's also used for a number of calculations, especially those which figure altitude and airspeed other than indicated.

[rudyjo]

If FS says your altimeter setting is wrong, it means the pressure setting on your altimeter is wrong. If you press 'B', FS will automatically set it to the current pressure setting. If you then adjust it manually, you will be un-setting the correct pressure. That make sense? 29.92 is the standard pressure setting. It's used for flying at a flight level. If instructed to fly at a flight level, always ensure your altimeter is set to 29.92Hg (or 1013mb), if flying at an Altitude, you use the pressure as said in the ATIS (or regional report if you have that information available)

I sometimes get the message that the altitude reading is incorrect and to press "B". It then changes the altitude and I assume
the barometric pressure. Within minuets, without changing the altitude on my part, the altitude on the meter changes and I again
get the message that the altitude is wrong and to press "B'. I have changed the barometric setting so it is set to what "B' had changed
it to. Again I will get the message that the altitude is wrong. The barometric pressure is not going to change that much in a few minuets.

[lnuss]

The barometric pressure is not going to change that much in a few minuets.

Not likely in the real world, I agree. But in FS, you may go through one controller's area, or the area of one reporting station, then a few minutes later get into another, each having a different altimeter setting. Remember, FS still has a few things that could be improved, and weather and ATC are two of them.

[nashvillecsx]

Here is the rule:

FAR 91.121 states that, when operating an aircraft below 18,000 feet MSL, pilots will maintain altitude by reference to an altimeter that is set to: 1) the current reported altimeter setting of a station along the route of flight and within 100 nautical miles of the aircraft; 2) the current reported altimeter setting of an appropriate available station; or, 3) in aircraft without a radio, the elevation of the departure airport or an appropriate setting available before departure.

Read more here:

http://asrs.arc.nasa.gov/publication...ne/dl9_low.htm

[rickattfield]

Not likely in the real world, I agree. But in FS, you may go through one controller's area, or the area of one reporting station, then a few minutes later get into another, each having a different altimeter setting. Remember, FS still has a few things that could be improved, and weather and ATC are two of them.

^^ What he said! FS real world weather is a pain. Some weather stations don't even exist any more so when you fly into their areas it'll jump back to standard setting. Also, just to clarify, when you press 'b', it doesn't change the altitude AND the pressure. The pressure setting is the only change. The altimeter gauge itself is just a fancy barometer. As you ascend, air pressure decreases, this is shown on the gauge as a clockwise movement of needles. Try it yourself, when you adjust the barometric setting, the altitude will wind/unwind. This is why it must be set at all