Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Sat, 04 Sep 2004 23:14:59 -0400 Message-ID: X-Original-Return-Path: Received: from sccrmhc13.comcast.net ([204.127.202.64] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 393366 for lml@lancaironline.net; Sat, 04 Sep 2004 19:36:40 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.202.64; envelope-from=olsen25@comcast.net Received: from pavilion (c-24-9-81-190.client.comcast.net[24.9.81.190]) by comcast.net (sccrmhc13) with SMTP id <2004090423361001600n89kle>; Sat, 4 Sep 2004 23:36:10 +0000 From: "Dan & Kari Olsen" X-Original-To: Subject: Re: [LML] P-static blew my VM1000, autopilot and trim indicator today X-Original-Date: Sat, 4 Sep 2004 17:37:55 -0600 X-Original-Message-ID: <011c01c492d8$36db00d0$6401a8c0@pavilion> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_011D_01C492A5.EC4090D0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.3416 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_011D_01C492A5.EC4090D0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit LML Gang, Thank you all for the quick replies so far on this topic! There has been some good discussion on points of failure and the importance of having a robust backup plan for primary flight instrumentation. For some background, my plane has vacuum attitude and DG, electric turn coordinator and the TruTrak autopilot that has its own gyros (no dependence on other gyros). I have felt that this is a pretty good set of redundancies. As soon as the autopilot crapped out (I view this as my backup to the other gyros primary gyros) I set the wheels into motion to make a 180 back into the clear and return home. In a previous life I designed the standby instruments (attitude, altimeter, VSI) for the Boeing 777. These were the first certified non-mechanical (LCD) backup instruments in a transport category aircraft. You would not believe the amount of testing and certification activity that went into these things. That's why they cost ~$30K each! Even with all of that, it still made me nervous that there is no mechanical backup. Because of my engineering experiences in the avionics industry, I have stayed away from EFIS to date. However, the allure of the benefits of EFIS is winning me over and if I build another plane it would likely include a certified EFIS system like Chelton but would DEFINITELY include a set of mechanical backups, no matter how tested the EFIS system is. The acid test I ask myself about each instrument is: "If this instrument failed in hard IMC, how would I proceed?" In the case of EFIS or the VM1000, the loss of an "instrument" is the whole thing! When I chose the VM1000 vs. discrete engine instruments I consciously decided that I could deal with loss of all engine instrumentation and finish the flight safely. My engine is a stone simple Lycoming 320, I can lean it manually and can use the clock for fuel management. In the case of EFIS, when that instrument fails you have just lost all of your primaries. I cannot deal with that and MUST have backups of all the primary flight instruments. Now, on to what concerns me the most about my system: ========================================== Is there a way for me to mitigate the problems I had yesterday? I know that the electrical components that are designed with the appropriate protection in them will do better and that was the case yesterday. Is there something that I can do externally to the existing "under protected" equipment that will give me better margins? If I had a metal plane I could electrically bond all control surfaces and put wicks on the trailing edges. Not an option with an e-glass plane. Don't even know how well the wicks really work in a carbon plane. Would chokes, zener diodes, shielding, etc. help? My EE training is primarily in the digital/computer area and is fading at that (I got the Marketing lobotomy a few years ago :) Thanks again for all the input! Dan ------=_NextPart_000_011D_01C492A5.EC4090D0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

LML Gang,

 

Thank you all for the quick replies so far on this topic!  There has been some good discussion on points of failure = and the importance of having a robust backup plan for primary flight instrumentation.  For some background, my plane has vacuum attitude = and DG, electric turn coordinator and the TruTrak autopilot that has its own = gyros (no dependence on other gyros).  I have felt that this is a pretty = good set of redundancies.  As soon as the autopilot crapped out (I view = this as my backup to the other gyros primary gyros) I set the wheels into motion = to make a 180 back into the clear and return home.

 

In a previous life I designed the standby instruments (attitude, altimeter, VSI) for the Boeing 777.  These were the = first certified non-mechanical (LCD) backup instruments in a transport category = aircraft.  You would not believe the amount of testing and certification activity = that went into these things.  That’s why they cost ~$30K = each!  Even with all of that, it still made me nervous that there is no mechanical = backup.

 

Because of my engineering experiences in the avionics industry, I have stayed away from EFIS to date.  However, the = allure of the benefits of EFIS is winning me over and if I build another plane it = would likely include a certified EFIS system like Chelton but would DEFINITELY include a set of mechanical backups, no matter how tested the EFIS = system is.  The acid test I ask myself about each instrument is: “If = this instrument failed in hard IMC, how would I proceed?”  In the = case of EFIS or the VM1000, the loss of an “instrument” is the whole thing!  When I chose the VM1000 vs. discrete engine instruments I consciously decided that I could deal with loss of all engine = instrumentation and finish the flight safely.  My engine is a stone simple Lycoming = 320, I can lean it manually and can use the clock for fuel management.  In = the case of EFIS, when that instrument fails you have just lost all of your primaries.  I cannot deal with that and MUST have backups of all = the primary flight instruments.

 

 

 

Now, on to what concerns me the most about my = system:

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<= /span>

Is there a way for me to mitigate the problems I had yesterday?  I know that the electrical components that are designed = with the appropriate protection in them will do better and that was the case yesterday.  Is there something that I can do externally to the = existing “under protected” equipment that will give me better = margins?  If I had a metal plane I could electrically bond all control surfaces = and put wicks on the trailing edges.  Not an option with an e-glass = plane.  Don’t even know how well the wicks really work in a carbon = plane.  Would chokes, zener diodes, shielding, etc. help?  My EE training = is primarily in the digital/computer area and is fading at that (I got the Marketing lobotomy a few years ago :)

 

Thanks again for all the input!

 

Dan

------=_NextPart_000_011D_01C492A5.EC4090D0--