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Date: Thu, 17 Jun 2010 06:07:38 -0400
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From: "Stan Fields" <sdfields@austin.rr.com>
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Subject: RE: [LML] Re: Legacy Glass Panel Suggestions?
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Hello Tom,

I was afraid someone would say that. Obviously looking at all the panels =
in our fleet, most have steam gauges as primary or backup. While I don't =
intend to joust with Thor, it may be unavoidable some day. It may not be =
possible to isolate all of the electronics from a lightning event but =
I'd hoped the state of the art had advanced enough to make that risk =
acceptably small. It would be interesting to know how many pilots flying =
dual EFIS panels with backup gauges were forced to rely on the gauges at =
some point.=20

Building electronic redundancy gobbles up panel space but perhaps with a =
little shuffling I can fit in a 3 pack - even with a small Legacy panel. =


Stan


-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of =
Tom Thibault
Sent: Wednesday, June 16, 2010 10:58 AM
To: lml@lancaironline.net
Subject: [LML] Re: Legacy Glass Panel Suggestions?

Stan,

You wrote "I am an electrical engineer and worked for 8 years at Cessna =
as an instrumentation engineer".  You also said "I want to eliminate =
"steam gages" but want equivalent electronic redundancy."

Please elaborate on your reasoning for elimination of steam gauges.  It =
seems that current generation GA certified airplanes still include steam =
backup.  For example, the Corvalis TT and Mooney Ovation web sites still =
shows airspeed, attitude, altitude steam gauges right beside the G1000 =
equipped panels.

Are you planning VFR only, for example?

For me, who went through the same decision process for an IFR solution =
in a 360 model, the answer came out retain the steam.  The =
considerations also included a history of prior p-static upsets of =
electronics in the cockpit when flying IFR through rain.  Of course, =
360s are mostly E-glass, so static wicks to drain the build up do not =
work, where they should on your Legacy.  Regardless, I believe in =
relying on multiple types of physics for flight instruments.  Pretty =
sure it was Brent Reagan who recommended that first here in the mail =
list.

In the event of p-static or lighting events, ALL the electronics could =
be taken out, no matter how isolated, redundant, or battery backed up =
they may be.  In that event, at least basic aircraft control info would =
still be available and a hand held comm/nav (not connected to any =
systems on the ship) could then be used to communicate and navigate out =
of the current instrument conditions.

Hopefully a reasoned, non-emotional, discussion will ensue.

Tom Thibault

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