[SOLVED] TAS on PFD tape & MFD don't match up...just me or a bug?

[amilotti]

Hey guys,

Now I'm not sure if this is normal or whatever that case might be, but in case it is indeed a bug and I'm right, I thought it worth it to post here.  I noticed that the airspeed reading on the tape of the PFD doesn't match up the text readout on the MFD...I've posted a screenshot for reference.  I first noticed I was having a bit of a hard time with my landings when I was only going off the speed tape, but after I went off of the readout on the MFD, it was much better.

Am I mistaken that the tape readout on the PFD is the TAS or no?

[Cameron]

Phillip will be with you shortly on this, however, if I rember correctly the left display is knts, while the right is TAS. As such, the difference is accurately displayed.

[amilotti]

you know, I think you're right.  after further review of the manual, the tape is the IAS and I guess the MFD is the TAS...i thought that might be the case but then let me ask you this...the speed limits for the different flap settings found in the manual...is that IAS or TAS?

Time for more practice landings.  

[Cameron]

you know, I think you're right.  after further review of the manual, the tape is the IAS and I guess the MFD is the TAS...i thought that might be the case but then let me ask you this...the speed limits for the different flap settings found in the manual...is that IAS or TAS?

That would/should be IAS.

[philipp]

Yep, the speed tape reads INDICATED airspeed.

As you climb higher, the air becomes "thinner", so the differential pressure in the pitot tube (that's how airspeed is measured) becomes smaller. Airspeed indication drops.

The readout on the MFD in turn shows TRUE airspeed, which is corrected for the altitude and temperature by the ADC (air data computer).

Philipp

[amilotti]

capice, thanks for indulging my silly questions guys.