Attitude indicator/ADAHRS, how many do you need for IFR..

[Graham D]

My initial post on this issue was re enforced by flight logic. The lancair accident may have been different from an adequate scan. Just watching a computer screen isn't good enough. I agree with Walt that his linked HSI may have agreed with his failed AH but I know when I am on departure on a black night or in IMC in a turbine with Glass, I am always cross checking alt and heading with the back up gauges or even the neglected compass that no one seems to look at these days. There is no need for all this triple redundancy ****, just old fashion airmanship. If youre flying in a straight line, chances are your wings are level

[Bavafa]

I firmly believe that a set of simple analog gauges that is not tied to the electrical system is far better redundancy for IFR flying. Right before I built my panel, I was set on two different/brand EIFS for redundancy and then I read a report of a plane with full electrical panel to crash in an IFR due to electrical melt down. My panel design changed to have a set of analog gauges and I am much happier this way.

[g3xpert]

Originally Posted by Finley Atherton

So the G5, Skyview and the G3X use air data (pitot and static) for the attitude display but will still display reasonably accurate attitude if air data is not available. But what happens to the attitude display if the air data is available but is not accurate - for instance blocked static or blocked/leaking pitot line.

Some time ago I did an approach in heavy rain and the pitch display on my Skyview intermittently rapidly oscillated + - (unusable) which I believe was due to water intermittently blocking the static port. Fortunately I also had a MGL Mini Extreme which does not use air data for attitude and it was rock solid.

I now have the single Skyview, the Xtreme, Trio and also the Sandia as our regulator in Australia wants TSO for IFR.

FIN
9A

Hello Fin,

Good question and this was taken into account when developing the Garmin G5 Flight Instrument. While it is true that under some circumstances the G5 will use air data to improve the precision of the attitude solution, it will not use air data whatsoever (to improve the precision of the attitude solution) unless GPS data is not available for this purpose.

This is another aspect of the G5 that distinguishes it from most other ADAHRS units. As long as the G5 is receiving data from either its internal GPS or several types of external GPS units (G3X/GNS/GTN/GPS20A), the G5 attitude solution is insulated from the impacts of blocked pitot and static ports.

Thanks,
Steve

[GalinHdz]

Originally Posted by g3xpert

Hello Fin,

Good question and this was taken into account when developing the Garmin G5 Flight Instrument. While it is true that under some circumstances the G5 will use air data to improve the precision of the attitude solution, it will not use air data whatsoever unless GPS data is not available for this purpose.

I am confused by this. If the G5 does not use air data then is the speed displayed air speed or ground speed and is the altitude Baro or GPS?

[BobTurner]

Originally Posted by GalinHdz

I am confused by this. If the G5 does not use air data then is the speed displayed air speed or ground speed and is the altitude Baro or GPS?

Re-read the whole sentence. If GPS is available then air data is not used to compute attitude.

[KRviator]

Originally Posted by g3 Expert

This is another aspect of the G5 that distinguishes it from most other ADAHRS units. As long as the G5 is receiving data from either its internal GPS or several types of external GPS units (G3X/GNS/GTN/GPS20A), the G5 attitude solution is insulated from the impacts of blocked pitot and static ports.

How well does it fare when it doesn't have access to either?

I'm considering installing a G5 as a backup, but don't particularly want to tap into the pitot/static lines if I can help it. By the same token I'd rather not have a GPS antenna parked on the glareshield for it if it will let me keep right side up without either of these elements.

[BobTurner]

Originally Posted by KRviator

How well does it fare when it doesn't have access to either?

s.

The real question is how it responds to faulty data. It's relatively easy to reject no data; much harder to detect and reject corrupted data.

[g3xpert]

Originally Posted by KRviator

How well does it fare when it doesn't have access to either?

I'm considering installing a G5 as a backup, but don't particularly want to tap into the pitot/static lines if I can help it. By the same token I'd rather not have a GPS antenna parked on the glareshield for it if it will let me keep right side up without either of these elements.

Hello KRviator,

Yes, as you probably know, the G5 air data sensors may be turned off if you do not wish to connect pitot/static lines. You may also turn off the GPS and GPS data fields if you do not wish to use the internal GPS to display GPS ground speed, altitude, and track.

Even when the G5 has neither airspeed nor GPS to improve the accuracy of the attitude solution, it does not have any inherent inaccuracies that a mechanical gyro based attitude indicator doesn't have.

Thanks,
Steve

[g3xpert]

Originally Posted by GalinHdz

I am confused by this. If the G5 does not use air data then is the speed displayed air speed or ground speed and is the altitude Baro or GPS?

Hello Galin,

This statement is referring to the use of air data to improve the precision of the attitude solution. Air data is only used for this purpose when GPS data is not available to eliminate the possibility of a blocked pitot/static from affecting the attitude solution (when GPS data is available).

If the G5 is installed with pitot/static connections, the airspeed, baro altitude, and vertical speed is all air data derived, not GPS.

Thanks,
Steve

[vic syracuse]

I also believe in redundant systems by different manufacturere's just so I don't happen to have a failure or hit the same software bug at the same time. I have dual AFS 5400's with a Dynon D-10 in the panel as well as a Trutrack Sorcerer autopilot. I am still not fond of integrated autopilots due to the potential to not have it when you might need it the most.

BTW my philosophy has paid off now. On a trip in an RV-7A that had just been upgraded from Chelton's to G3X screens we had the screens fail multiple times in IMC while climbing through an 8K' thick layer. We were solid IMC. Having the Sorcerer and the D-10 made it no problem. Yes, we hit a bug that was locking up the Garmin screens when loading the flight plan changes from ATC via the IPAD. After 3 failures and waiting for them to reboot I figured out what the new owner was doing and had him stop making changes. Once on top in VFR we duplicated the problem, as I wanted to know for sure before we started back down.

[ed. Re-reading this thread after awhile. Thought....Vic, did you loose ALL screens in IMC simultaneously or did you loose one or the other with the info moving to the remaining? I may be reading this wrong, but I interpretted what you wrote as you lost all screens at once. I had one EFIS reboot due to bad cooling on my part, and the info all moved over to the screen that had good cooling (very hot day with plane outside a long time). Just curious, and thanks in advance.

v/r,dr]

BTW there is also a good story about the software in the F-22's, some of the most tested s/w ever put in an airplane. On a deployment to Japan while crossing the International dateline all of the screens went dark, so the story goes. Luckily they were with a tanker to bring them back to Hawai.

Vic