# Tag Info

0

As already stated, pressure is effectively the weight of the air above the aircraft. If you were (for example) to double the absolute temperature of the entire atmosphere (from say 300K at sea level to 600K then the atmosphere would double in volume, assuming it’s an ideal gas, which isn’t a million miles from the truth, and pressure altitudes would ...

0

By definition temperature is not factored in to calculation of pressure altitude. Pressure altitude is always the indicated barometric altitude with 29.92 used as a barometric offset. Temperature will affect the altitude of aircraft flying at pressure altitude though.

2

Because Pressure altitude is a measure of the weight of the air above you. Temperature does not affect that. Heating the air just makes it expand. It still weighs the same.

3

The picture you have displayed is correct. But, your understanding of what it is saying is incorrect. The picture is explaining the reason your Indicated Altitude will change with temperature for the same True Altitude. And, your True Altitude will change with temperature (a potentially dangerous situation) for the same given Indicated Altitude. Your ...

5

You need to correct your pressure altitude (FL85) for the barometer setting QNH first before you apply the temperature correction. I assume a 30ft / hPa offset here: $\textrm{barometric altitude} = \textrm{pressure altitude} + (\textrm{QNH} - 1013.25)\cdot 30 = 8500 -907.5 = 7592.5 \textrm{ft}$ Based on the pressure difference between sea level and your ...

3

The simple answer is, usually the altimeter setting does not change fast enough for it to be an issue. Near ground level, one-hundredth of an inch of mercury (00.01 inHg) corresponds to roughly ten feet of pressure altitude. Thus one inch of mercury corresponds to one thousand feet of altitude. (This rough rule of thumb can be seen by looking at a lowest-...

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