Does IAS read higher in cold air?

FORANE

En-Route
Joined
Mar 7, 2013
Messages
3,536
Location
TN
Display Name

Display name:
FORANE
Does indicated airspeed read higher with a lower outside air temperature?

Cold air is more dense so more ram air pressure (meaning possibly greater IAS reading) yet IAS is based on a difference between static and ram air (meaning possibly canceling each other out?).
 
Well, most of us don't fly TAS, so the more correct way of saying it is that TAS goes down when it's colder. Even more correct is that TAS goes up with density altitude (at a rate of about 2% per 1000 feet DA), so if DA is really low, you'll be slow.
 
Well, most of us don't fly TAS, so the more correct way of saying it is that TAS goes down when it's colder. Even more correct is that TAS goes up with density altitude (at a rate of about 2% per 1000 feet DA), so if DA is really low, you'll be slow.
I don't know that most of us fly a constant IAS either...unfortunately the OP didn't specify the constant.
 
Well, most of us don't fly TAS, so the more correct way of saying it is that TAS goes down when it's colder. Even more correct is that TAS goes up with density altitude (at a rate of about 2% per 1000 feet DA), so if DA is really low, you'll be slow.

It's not more correct.

These two statements are equally correct:
At higher density altitude, TAS > IAS
At higher density altitude, IAS < TAS
 
I just use the GPS if I want to see my speed over the ground....:confused:

I think the answer would be more clear if the question discussed the issue correctly....the answer needs to discuss instrument error. :stirpot:
 
It's not more correct.

These two statements are equally correct:
At higher density altitude, TAS > IAS
At higher density altitude, IAS < TAS
They are also equally incorrect.
 
Provided you hold all the other variables constant, a higher density altitude will result in a given calibrated (or in my airplane "true indicated") airspeed will result in a higher true airspeed.
 
Back
Top