The following is a direct quote from the GRT Yahoo Groups which I thought many VAFWWW readers might like to see:
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Selecting an EFIS
Posted by: "Rick Pellicciotti" [email protected] rpellicciotti
Mon Jun 2, 2008 6:21 pm (PDT)
I know a lot of people in this group have already purchased their
GRT EFIS. Others though, are here because they are doing research
on which EFIS to buy. I wanted to share some experiences that I
have had recently because I think it will help both groups.
A little background on me:
I am a GRT customer and I am satisfied with my EFIS. I am also a
voting member on the ASTM committee for Light Sport Aircraft.
Recently, a working group was formed to develop proposed standards
for IFR operations of Light Sport Aircraft. I am a member of this
working group. One of the things that came out of these working
group meetings is that some EFIS systems (especially the inexpensive
ones) derive their attitude depiction data from GPS and pitot data.
In other words, if you lose GPS or your pitot (blockage, icing,
etc), your ATTITUDE depiction will become INACCURATE.
I felt like I did my homework on EFIS systems before I bought my
Horizon 1 but frankly, I missed this somehow. I picked up the phone
and has several conversations with GRT and also with other EFIS
manufacturers. What I found out was very interesting. The GRT EFIS
does not rely on pitot data for anything except airspeed. If you
lose pitot or GPS, your ATTITUDE indication is not affected. The
most startling thing that I found out during my research is that the
FAA CERTIFIED, Chelton system does have the problem of inaccurate
attitude data with the lost of pitot input. Their manuals state
that the attitude indication can be off as much as 2.5 degrees when
pitot data is not available. The Dynon manuals state that attitude
indications are not reliable if pitot data is lost.
Needless to say, I was surprised by this but pleased that the GRT
systems do not have this quirk/problem.
Rick Pellicciotti
EZrg N818KD, Race 51
Dual Horizon 1, GNS420, SL30, GPS18, EIS4000
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Naturally I am biased since I have a three screen GRT EFIS panel in my RV-10 and am putting a two screen GRT EFIS panel in the RV-7 which is under construction.
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Selecting an EFIS
Posted by: "Rick Pellicciotti" [email protected] rpellicciotti
Mon Jun 2, 2008 6:21 pm (PDT)
I know a lot of people in this group have already purchased their
GRT EFIS. Others though, are here because they are doing research
on which EFIS to buy. I wanted to share some experiences that I
have had recently because I think it will help both groups.
A little background on me:
I am a GRT customer and I am satisfied with my EFIS. I am also a
voting member on the ASTM committee for Light Sport Aircraft.
Recently, a working group was formed to develop proposed standards
for IFR operations of Light Sport Aircraft. I am a member of this
working group. One of the things that came out of these working
group meetings is that some EFIS systems (especially the inexpensive
ones) derive their attitude depiction data from GPS and pitot data.
In other words, if you lose GPS or your pitot (blockage, icing,
etc), your ATTITUDE depiction will become INACCURATE.
I felt like I did my homework on EFIS systems before I bought my
Horizon 1 but frankly, I missed this somehow. I picked up the phone
and has several conversations with GRT and also with other EFIS
manufacturers. What I found out was very interesting. The GRT EFIS
does not rely on pitot data for anything except airspeed. If you
lose pitot or GPS, your ATTITUDE indication is not affected. The
most startling thing that I found out during my research is that the
FAA CERTIFIED, Chelton system does have the problem of inaccurate
attitude data with the lost of pitot input. Their manuals state
that the attitude indication can be off as much as 2.5 degrees when
pitot data is not available. The Dynon manuals state that attitude
indications are not reliable if pitot data is lost.
Needless to say, I was surprised by this but pleased that the GRT
systems do not have this quirk/problem.
Rick Pellicciotti
EZrg N818KD, Race 51
Dual Horizon 1, GNS420, SL30, GPS18, EIS4000
--------
Naturally I am biased since I have a three screen GRT EFIS panel in my RV-10 and am putting a two screen GRT EFIS panel in the RV-7 which is under construction.