I’ve just read of a report from the USA, on a new installation.
If this is how it is supposed to work, it is IMHO outrageous. This is worse than the A330/AF447, where they still had pitch/roll data.
source?
If airspeed is lost, it will remove airspeed and altitude tapes, as it can not be displayed correctly. It will display “CHECK PITOT HEAT” and after a while “ADAHRS FAIL” Then attitude information is no longer displayed.
This behavour is not unique to Aspen. All other AHRS systems which have air data input will sense this problem, and degrade to a level where they will remove attitude information.
The other way around is also true, if the AHRS will sense different data then is expected on pitot static data, it will also give errors (you will see these during pitot static ground testing).
It appears to remove more than attitude information in this case.
Source? From a US TB20 owner.
Please give accurate information. Can easily simulate this on my demo unit. What would fail according them? What went wrong anyway? Why is it outrageous? You suggest the loss of pitch / roll information, which happens on all GA types of glass cockpit in this situation (and using a single sensor / input), and it is described in the pilot guides.
It may be in the pilot guides but it is worth pointing out because I am sure many owners are not aware of it.
If everybody was aware of everything, shut down the internet because it would be pointless.
The reason this happens is actually quite subtle, and is to do with the way the information is derived from airdata. A clever avionics engineer like yourself, and a very clever owner-pilot who understands the systems really well, will know about this. The rest?
Aspen give you the most bang for the buck, and are very popular with both owners and installers, but that doesn’t put them above scrutiny.
As for accurate information, yeah, I wish, Jesse, that you posted that comment after every time somebody else tosses a useless (sometimes deliberately useless) one-liner into a forum. I am not perfect but I do my damnest to keep EuroGA informative.
If you can “easily simulate” this on your demo unit, why not do a video of it and post it here, so that everybody can learn.
That is a very valid point. Often people spend several thousends on equipment, not to know how to operate it completely.
Don’t get me wrong, I don’t think their is anything wrong discussing that here, it’s very good, and I am happy you provide a nice website / forum to do this. Sometimes however it feels it can damage manufacturers.
In this case it seems the pitot had been blocked somehow, and that the pilot didn’t notice this before his Aspen EFD was complaining. A valid question would be, what if he didn’t had the Aspen, he didn’t seem to be aware that it was blocked, and that his analog instrument could have been off as well. Especially as the TB has just a single pitot head like most SEP.
I will see what I can do on a video.
The Aspen manual is very specific on the failure modes and it is required by the pilot of an EFIS to have that knowledge. After all, EFIS aircraft require a differences training per EASA. The G1000 behaves in the very same way as far as I know.
However, I do not know why the certified EFIS use air data to erect the attitude indicator when every mobile phone and Playstation controller can directly measure the g-vector.
This is worse than the A330/AF447, where they still had pitch/roll data.
A GA retrofit EFIS is worse than the Airbus 330 avionics — that is really outrageous 
Jesse, can you explain to me why glass avionics (not only Aspen, but G1000 as well) remove attitude information when airspeed and/or groundspeed is unreliable?
My mechanical attitude indicator doesn’t even have an airspeed input, and still displays attitude correctly. My own algorithm on a tablet computer displays an attitude correctly and doesn’t have an airspeed input as well (and doesn’t use GPS for the attitude data). All you need is a 3D acceleration sensor and assume unaccelerated flight, just like the mechanical AI does…
I took off once with a blocked static port on the pitot. The airspeed indicator went bananas when I climbed. That was an analogue unit and I had a stand alone GPS so I had ground speed at least and took a circle and landed.
All the eggs in one basket principle is dubious to start with, and when the failure modes are everything but intuitive then I agree, this is outrageous.
