| On one of my first solo take-offs after "finishing" my IVP, I had a GADAHARS failure, on climb-out.
I was VFR and the weather was good, so it wasn't an extreme emergency, but I was pretty happy I had installed full size airspeed, attitude and altitude steam gages to back up my Cheltons.
A new software update quickly fixed the GADAHARS which has performed flawlessly for the last 250 hours. But I'm still happy to have the backup gages.
My steam gage attitude indicator does not have an internal battery backup. If the recession ever ends, I may look into replacing that unit with one that has a battery backup.
John Hafen IVP 413AJ
Stan,
Were it not for the mechanical backup guages I installed in my IVP we would not be having this conversation. If you are only concerned about lightning you are only looking at a small portion of the hazard. Brent Regan has posted extensively on this subject-- his remarks are worth their weight in gold.
Jeff
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.
-----Original Message-----
From: Stan Fields < sdfields@austin.rr.com>
To: lml@lancaironline.net
Sent: Thu, Jun 17, 2010 5:07 am
Subject: [LML] Re: Legacy Glass Panel Suggestions?
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.
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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