Airbus PFD speed discrepancy

Hi,

does anyone know why the Airbus PFD gauges always show lower speed above the speed bar on the left (see the picture red arrow). The speed indication there is always lower sometimes by 40-50knots. This is compared to the speed bar in the same gauge (picture green arrow). The gauge I am showing is Z_AB320KM!PFD from Z_AB320KM CAB but I also noticed the same discrepancy in AB380 PFD gauge from Z_AB380KM_WH CAB. Initially I thought that this is a correction for the wind speed but it is not related to the wind velocity at all.

Thanks for any response.

Peter

244 is probably your TAS True Airspeed

TAS and GS (ground speed) most always varies from IAS (indicated airspeed)

It's unusual for a Ken Mitchell gauge to be "out" by that amount, but no-one's perfect! I'd say it's the speed tape (reading 260 kts) which is out by about 14 kts in this case. Fortunately Ken's gauges are widely used so you may find an updated or corrected version in the FS2004 Panels Library here.

Many thanks Tim,

There was actually one update to AB380 panel, which corrected some knobs but the PFD speed discrepancy did not seem to be corrected. I am bit surprised since the airspeed flow to a gauge should be straight forward. In my cockpits, I actually pasted some simple digital air speed window over the wrong indication in the PFD to fix it, but I am still curious what is causing this. Perhaps Ken Mitchell (if available) can explain. This is more the curiosity than necessity! His gauges are great!

Cheers

Peter

Hi Peter, you could try replacing the faulty Z_AB320KM!PFD with the PFD from Ken's original panel:

 

https://www.flightsim.com/vbfs/fslib.php?do=copyright&fid=90196

That is what I thought Allen. But this speed (above the bar) is lower whether there is a head wind or tail wind? Whether I select True air speed or indicated air speed in settings!

What I see, and I fly the bus in RWL is that you are in managed speed, while not indicated the bus accepts up to 10 fast/ 5 slow of the managed target. The clue as to whether selected or managed is the color of the speed target magenta vs blue. And the bus does its own thing every once in a while . We have a saying, "oh, it's doing that again!" Hope I helped!

 

 

Sent from my iPhone using Tapatalk

Hi Tim, did as you suggested have downloaded the original panel but no joy. Have taken aircraft to 360 kts and the indication above the speed bar in PFD was 312 knots? Clear sky, no wind! Strange

Hi Tim, did as you suggested have downloaded the original panel but no joy. Have taken aircraft to 360 kts and the indication above the speed bar in PFD was 312 knots? Clear sky, no wind! Strange[ATTACH=CONFIG]199782[/ATTACH]

 

Not sure about your original gauge, but with this gauge could it be ken had it coded for the the strip to show in MPH and the digital readout in Knots? 360 MPH does equate to 312 Knots

Possibly the read-out is reversed. But in this picture my aircraft actually flew at 360 kts, which also showed on other gauge I have (not shown in the picture) Which would be 666 km per hour.

A (tentative for now) BIG thumbs up!:D

il.

Are you sure you have tried both TAS and IAS in the settings/realism menu? I use this panel and just tested it on my system, started with IAS and the digital and tape speeds are the same, then switched to TAS and was able to replicate the issue you were having, took it up to 300 kts, tape showed 300, digital showed 268, zero wind, FL09

Hi,

you are right in IAS setting the speeds are the same. But I believe that these should also be the same in the TAS setting.

Simple. Don't set settings to TAS. IAS is what determines flap being torn off, gear extension speed, and lift. You need all that to keep a plane in the air.

 

Tas is just for getting home on time, and that's the last thing to care about when flying. Safety, safety, safety. Land safely before the fuel runs out. And find a hotel.

Hi,

you are right in IAS setting the speeds are the same. But I believe that these should also be the same in the TAS setting.

 

no they will not be the same, as you gain altitude into thinner air there is less air molecules to enter the pitot tube, so your tas will be higher than your ias

 

**edit: Misread your post, yes, if you select TAS to be displayed then probably both indicators should be displaying TAS, not 1 as TAS and 1 as IAS, but I guess that depends on how it was coded, so tiger1962 might have your answer in the following post

Hi,

you are right in IAS setting the speeds are the same. But I believe that these should also be the same in the TAS setting.

 

Both TAS speed figures will only be the same if they have both been coded to show both IAS and TAS speeds, it looks like that's been missed on the figures above the speed tape. It can easily be fixed if you don't mind editing .xml gauges, with a quick copy & paste in Notepad:

 

Open the PFD.xml gauge in Notepad and scroll down to the second section titled AIRSPEED.

On the line beginning with

Now scroll down the section titled TEXT.

In the first element, replace the text: (A:AIRSPEED INDICATED, knots) with (A:Airspeed select indicated or true, knots) and save the file.

Hi Tiger,

many thanks. Sounds like a great piece of advise. Please let me know how do you open (edit) a gauge in notepad. Both these gauges are part of CAB (Z_AB320KM and Z_AB380KM_WH). I work with notepad a lot in TTools, scenery and other files but am not familiar with gauges.

The gauge files have to be extracted from the .cab file, which is a type of .zip archive. Most of the Winzip-type programs can extract from .cab files, but I'd advise you to only use cabdir.exe to create a new .cab file - just drag and drop the gauge folder over the cabdir.exe to create a new .cab file.

If this is truly how to fix it without messing with other code, then use Notepadd ++.

No, use notepad. (not ++).

Notepad++ can add unwanted code too.

I don't know, il. I use Notepad++ to open xml files, and edit them. I've never yet had it add anything to a file I didn't type myself. Not once.

Then again, I'm probably using it wrong, or something :rolleyes:

Wouldn't be at all surprised.

 

Have fun, all!

Pat☺

Hi Pat:D,

It has a setting in which it shows things like spaces, hardreturns, etc. That will mess up your files good. Also notepad++ does not save open files automatically on closing, or offer to do so. You need to close individual tabs for that.

To be on the safe side, use (, and advise) notepad. Can't ever go wrong with that.

It has a setting in which it shows things like spaces, hardreturns, etc.

Hey, il :D

I must have that turned off. That explains that!

 

Also notepad++ does not save open files automatically on closing, or offer to do so.

That I was aware of. I save with tha little tab on the toolbar. Always. I do the same thing with notepad, though. I don't trust "automatic" requests to save or anything. I always save manually somehow before I close a file, changed or not. Force of habit, I guess.

 

But, from now on, it's Notepad all the way. I like the versatility of ++, but if it's a problem, I'll stick with recommending Notepad alone. Personally, though, I will keep using Notepad++. I really like it.

Have fun!

Pat☺

Keep using Notepad++ if you like.

 

The concept that spaces and returns will cause problems in FS is nonsense.

 

Notepad adds spaces and returns also. If it did not, theneverythingwouldlooklikethisandbeononeline.

 

Go to the gauge forum at FSdeveloper and ask how many folks there use Notepad++. I think you would find the majority of them do.

 

peace,

the Bean

Yeah, I use Notepad++ all the time editing files in FSX and for my website. To say you shouldn't use it is just plain nonsense.