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Date: Thu, 16 Dec 2004 18:42:18 -0500
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From: "Bob Pastusek" <rpastusek@htii.com>
Subject: RE: [LML] Chelton vs Avidyne
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Mike Aarons wrote:

Starting to think about a panel for my 4PT...

Mike,

There are several EFIS options available, and more coming monthly. The
Chelton system is probably the "top of the line" in integrated systems
available to experimentals today. Talk to Kirk Hammersmith
(kirk@direct2avionics.com); www.direct2avionics.com, if you're looking at
this system as he specializes in building panels around the Chelton. Kirk
used to run the avionics shop at Lancair before starting his own business,
and has been a very good man for us to work with over a number of years.

Another to consider is OP Technologies. www.optechnologies.com I believe
that Ed Smith in Chesapeake is using this system in his IV-P. He's still
building like us, but has researched these things pretty well and might
offer some other comparisons. Don't have any first-hand experience with
them.

We've installed a BlueMountain system in Jim White's IV-P and really like
the layout and features.  www.bluemountain.com  Jim chose a dual screen
layout to be able to fly easily from either seat, but the redundancy is only
in the display; both are driven from the same processor and air data
computer. We've not yet flown it (Spring of 05?) but the installation and
ground checks so far are going well. Greg Richter at Bluemountain has also
been very good to work with. His system is a lot less expensive than the
Chelton, possibly the least expensive of the "full featured" systems now
available for experimental aircraft, but it has some very nice extras,
including an integrated autopilot. The other systems I've looked at fall "in
between" in performance and capability.

One disadvantage of any EFIS is that some failure modes can instantly blank
a very large part of your instrumentation. All systems I've looked at have
provisions to aleviate this, and the marketing hype would lead you to
believe that they are immune to such failures, but my view is that it simply
isn't so. That means you need to include reliable backups for critical
instruments in your panel, and give serious thought about how you power and
hook them up. This is an area where folks like Kirk Hammersmith, as well as
some of the older heads on the LML, can really be of help. Even the "heavy
iron" machines have problems with this--we had an alternator on each engine
in the F-4 Phantom capable of carrying the full electrical load of the
aircraft, and they were coupled with a fancy electronic interconnect that
matched phase and frequency. The "standard procedure" for a lost alternator
or part of the electrical system was to turn off the bad equipment and cycle
the bus tie relay to reconnect the system components. The most likely result
of this procedure (in my experience) was to knock the good alternator off
the line--and a very dark airplane at night. Ditto for the A-6. So my panel
is provided with dual, independent power sources, and (at least for now)
they are not interconnected. Just one opinion and approach...

Bob Pastusek