altimiter problems

[cheezyflier]

i am having a problem with fs9. my altimeter says one thing, the text read out at the top of the screen says another, and atc says something completely different. i only fly fs9 ifr with major storm because i can't do it with fsx. can anyone tell me how i might fix my altimeter problem?

[thefrog]

Press B - unless you've already tried that!
Regards
Frog

[cheezyflier]

well, that explains why "D" doesn't work!!!
i am going to try that right now and see

[dominique]

i am having a problem with fs9. my altimeter says one thing, the text read out at the top of the screen says another, and atc says something completely different. i only fly fs9 ifr with major storm because i can't do it with fsx. can anyone tell me how i might fix my altimeter problem?

ATC messages only change every so often (15 minutes If not mistaken) so the announced setting can be different from the actual atmospheric pressure. And B is indeed the key to reconcile the altimeter with the proper setting.

[myles]

'D' resets the Direction Indicator to correct for gyro drift, if I remember correctly!

Best,
Myles

[cheezyflier]

thank you! it does indeed work at least part way. hitting the "B" key gets me to the assigned altitude and gets atc off of my back, but the read text at the top of the page doesn't show where i actually am. for example, if i am at 10,000 ft, the text says i am at 9438 or somewhere there abouts.

[pfflyers]

I don't fly with the text enabled so I've not noticed that discrepancy.

I do know that altimeters are not extremely precise measuring intsruments.

Also you must remember that unless you are flying in dead calm air you will always experience some variation in your altitude as the air mass you are flying in moves.

I suspect that the text read out is giving you an instataneous readout of your exact altitude. Your altimeter cannot match that level of precision. That is why many aircraft are equipped with radar altimeters.

[fliger747]

The text altitude is the sim calculation of you altitude above the geoid (think MSL). Altimetery must be corrected for temperature and pressure to agree with the actual altitude. As the atmosphere pressure and temperature gradient (especially at altitude) is seldom close to "standard" there will be differences. We flew over the Summit of Denali (20,320') one time at FL250 and recorded 1200' on the radar altimeter.

Radar altimeters only measure the distance above the surface, not altitude. We do use them as reference in determining Decision or Alert height on some precision inst approaches.

The main thing about altitmeters, that they read airport elevation (with the appropriated setting applied) and thta at altitude everyone has the same differential so that altitude separation of traffic and terrain clearance is maintained.

T.

[pfflyers]

Sorry about any confusion I might have caused when refering to radar altimeters. I was merely comparing their relative accuracy, not suggesting that a radar altimeter could be used in place of a barometric altimeter.

fliger747 - the fact that you flew over Denali at an actual altitude of 21,520' when your barometric altimeter read 25,000' might be a good example of what cheezyflier is seeing.

[cheezyflier]

wow! thanx for that, i learned something! what you guys say lines up pretty well with my experience also, because i only fly fs9 in heavy storms, so the pressure would definitely have an effect then.
cool deal

[Sunny9850]

If you are flying below FL180 or 18000ft then your altimeter will read what the text from SHIFT+Z tells you...
If you manually set the Kollsman Window to what ever ATC tells you the current setting is or you use the "simplified" version of pressing the altimeter reset key (default is B)
If you are flying in the flight levels in the ConUS above 18000ft then your altimeter must be set to 29.92 and you will see a difference between the meter reading and the SHIFT+Z text in almost all cases.....but ATC will be ok with that....since that is the way it works in the real world.

In certain real world conditions a VFR plane flying at 17500 would end up too close to an IFR airplane flying at FL180 due to that difference in altimeter setting even with both pilots flying spot on and having set their Altimeter correctly....and in those situations FL180 and FL181 are not available to ensure vertical separation minima.

Stefan

[fliger747]

In that situation, FL 190 is the lowest useable Flight Level....

[Sunny9850]

LOL of course you are correct....I had a little math problem there :D 18000 + 1000 does of course not equal FL181