IAS vs AoA

[Weasel]

I am working on some flight testing and am interested in a few facts if any of you care to offer you expertise.

If weight is constant, will the Angle of attack stay the same at the same IAS regardless of density altitude?

[ChiefPilot]

Originally Posted by Weasel

I am working on some flight testing and am interested in a few facts if any of you care to offer you expertise.

If weight is constant, will the Angle of attack stay the same at the same IAS regardless of density altitude?

No, not without additional constraints. Is the aircraft turning? Same weight, but varying bank angle will require a different AoA to remain at the same altitude. Along those same lines, are flaps up or down?

If weight is constant in unaccelerated/1G flight and the aircraft configuration is unchanged, then yes, AoA should remain approximately constant(*).

* = ignoring the things that become more important as you approach Mach 1.

[David-aviator]

Originally Posted by Weasel

I am working on some flight testing and am interested in a few facts if any of you care to offer you expertise.

If weight is constant, will the Angle of attack stay the same at the same IAS regardless of density altitude?

Yes.

The AOA and IAS will be the same but true airspeed will change depending on air density.

At a high altitude airport (less dense air) the take off will occur at a given AOA and IAS, the same as at sea level, but true airspeed will be higher to create sufficient lift to fly.

In severe operating conditions this can affect tires, the speed could exceed their ground speed limit.

As Brad says, only if the conditions are constant and unchanged.