I received a post from someone flying the Blue Mountain EFIS Lite in
their RV and am passing it along to the list.  Much thanks to Sam
Buchanan for the report.

-Kirk

Forwarded Message:

--> RV-List message posted by: Sam Buchanan

For the past six weeks I have been flight testing a Blue Mountain
Avionics
EFIS/Lite in my RV-6. I first saw the BMA EFIS/One and Greg Richter at
OSH
2001 and was very impressed with the capabilities and
potential of a gyroless IFR panel. The announcement of the EFIS/Lite
coincided with my decision to upgrade the panel in 399SB so I could
regain
IFR currency.

I paid a deposit for the Lite in early January expecting delivery in
6-8
weeks, but it was not until the first of June that I actually got my
hands on
a unit. The purpose of this post is not to expound on the
various delays in receiving the product; I fully expected some delays
to
occur as the Lite was brought to market, especially considering no
similar
product had been introduced to the experimental aviation
community.

I have now flown three individual Lites in an effort to achieve
satisfactory
and expected performance from the instrument.  Unfortunately, none of
the
units had all features working at the same
time. Greg Richter, guru in chief at BMA, has been very receptive of
the
multitude of observations and suggestions I made about the unit and
incorporated many changes to the software code based on my flight
testing.
The display is much more user friendly now than it was six weeks ago.
Admittedly I received the first unit early in the production cycle, but
Lites
and EFIS/Ones are presently being shipped to customers.

However, the most serious problem is with the AHRS platform. This is
the
solid state "gyro" system that forms the basis for the entire box. (By
the
way, it is my understanding the AHRS in the Lite is identical to that
in the
EFIS/One.) The benchmark I initially used to test the AHRS as to see if
the
system could remain stable in a 360 degree standard rate turn. This is
an
essential function since the standard rate turn is the maneuver upon
which
all IFR flight is based. Unfortunately, the AHRS "cutout" after about
280
degrees of turn with a resulting drift into erroneous bank and pitch
displays, and this problem was repeatable and predictable. What was
especially troubling was that the error occurred with no warning flag.

Attempts by Greg to tweak the software were unsuccessful and this
problem
among other AHRS and pitot errors was present in all three boxes I
flew.

I have returned all the units to Blue Mountain Avionics. I still feel
very
strongly that AHRS is the way of the future and I intend to have the
technology in my plane; I would very much like it be from BMA. Greg
Richter and I have a very pleasant relationship and hopefully I will be
able
to fly a fully functional EFIS/Lite in the not-too-distant future.
Greg
emailed me today stating that he thinks he has a grip on the problems,
so I
suppose time will tell. However, "flying" the unit on a bench cannot
substitute for hundreds of hours in an aircraft in actual flight.

The purpose of this post is to update those of you who are considering
the
purchase of BMA or other AHRS technology. Please keep in mind this is
very
new stuff and no doubt debugging time needs to be a part of your plans
if you
decide to install this or similar equipment. Please keep in mind that
AHRS is
the backbone of BMA's autopilot and terrain mapping equipment. I am
also
going to be very interested in actual flight experience of builders who
are
incorporating the new TruTrak auto pilot systems since it is my
understanding
they also use AHRS.

The most serious concern I have is for flight into IMC with new AHRS
boxes.
As all IFR-rated pilots know, IFR flight is a very serious undertaking.

Personally, I am going to need to see the AHRS systems rack
up a bunch of time before I point 399SB into the clouds with little but
AHRS
keeping me safe. I will have some limited backups on board, but the
builders
who are considering the EFIS/One with only the Lite for backup (or
similar
systems from other manufacturers) are putting ALL their IFR eggs in one
AHRS
basket!

I will keep the RV community informed as to future developments of this

matter and I eagerly await the impressions of other builder/pilots who

develop a knowledge base of this new technology.