X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 05 Aug 2011 10:37:37 -0400 Message-ID: X-Original-Return-Path: Received: from vms173009pub.verizon.net ([206.46.173.9] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5082027 for lml@lancaironline.net; Thu, 04 Aug 2011 13:33:23 -0400 Received-SPF: pass receiver=logan.com; client-ip=206.46.173.9; envelope-from=n5zq@verizon.net Received: from p6520y ([unknown] [173.72.167.62]) by vms173009.mailsrvcs.net (Sun Java(tm) System Messaging Server 7u2-7.02 32bit (built Apr 16 2009)) with ESMTPA id <0LPE00LQMZEE9EI1@vms173009.mailsrvcs.net> for lml@lancaironline.net; Thu, 04 Aug 2011 12:32:39 -0500 (CDT) X-Original-Message-id: <35A8CD0CC90F44539952CDE0498C4B45@p6520y> From: "Bill Harrelson" X-Original-To: "Lancair Mailing List" References: In-reply-to: Subject: Re: [LML] Fw: Re: Re-doing my panel - carefully thinking through failures X-Original-Date: Thu, 04 Aug 2011 13:32:37 -0400 MIME-version: 1.0 Content-type: multipart/alternative; boundary="----=_NextPart_000_02F3_01CC52AA.F9FC4800" X-Priority: 3 X-MSMail-priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 15.4.3508.1109 X-MIMEOLE: Produced By Microsoft MimeOLE V15.4.3508.1109 This is a multi-part message in MIME format. ------=_NextPart_000_02F3_01CC52AA.F9FC4800 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi Fred, I like your simplified electrical diagram. I reached almost exactly the = same solution in designing the power grid for our IV except I have 3 = alternators and 3 batteries. Other than that...very similar, big Schotky = diodes feeding the essential bus from 3 independent electrical systems = and the avionics bus powered by two systems, both diode isolated and = able to crosstie to the third. I also have iron gyros, and round = airspeed and altimeter backup instruments. I am no longer young but I = have managed to retain my stupidity. I=E2=80=99ve not yet achieved the = level of intelligence and maturity that you have as I still have = aspirations for trans Pacific (and worse, trans Antarctic) flights. = Maybe I=E2=80=99ll see you in OZ one day. Bill Harrelson N5ZQ 320 1,950 hrs N6ZQ IV under construction From: Frederick Moreno=20 Sent: Thursday, August 04, 2011 9:30 AM To: lml@lancaironline.net=20 Subject: [LML] Fw: Re: Re-doing my panel - carefully thinking through = failures Brent has written much on this topic including "In my "Glazed and = Confused" presentation on "Glass Cockpits" I say that flying an aircraft = with a non-certified, non TSO'ed glass standby (Dynon et al) is like = jumping out of an airplane with only your main parachute and your = standby plan is the fact you are wearing real soft socks." I concur. =20 When I was young and stupid (not long ago) I had thoughts of long = overwater (think trans-Pacific) flights. I also have experience with = failure modes assessment analysis (FMEA) which frequently shows up = failure modes easily over looked. After reviewing various electrical = and instrument configurations I arrived at a system design which is = shown in simplified form in the attached sketch. It consists of two = alternators, two batteries, four busses, and a lot of opportunities for = cross tie. I use dual Chelton screens, with PFD off the essential buss = (many sources of power), the MFD off of the avionics bus (which has many = sources of power), and back up electric attitude indicator (on = essential buss), turn and bank (essential buss) and air speed and = altitude indicators.=20 You show me the failure and I can show you the automated or manual = work around. And critical stuff is all double protected with circuit = breakers and surge arresters (not shown).=20 But even this diagram is not as safe as it could be. What about = something simple like: a battery relay decides to go flotch? (One = already has done so.) That causes a main bus to go south forcing you to = a cross tie solution, not ideal. So not shown are by-pass switches and = fuses around the relay solenoids I added "just in case" to provide = redundancy on all supply routes.=20 I have a mechanical and electrical fuel pump. And I have an = electronic ignition and a magneto.=20 Two of everything, independent power modes, independent pathways, = cross connects, multiple layers of electrical spike and surge protection = and independent and different principles of gyroscopic display and = electrical power supply. Now one begins to achieve realistically (and = defensible) high levels of reliability. =20 If I could only achieve the same with the pilot.=20 Fred Moreno =20 =20 =20 =20 -------------------------------------------------------------------------= ------- -- For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html ------=_NextPart_000_02F3_01CC52AA.F9FC4800 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
Hi Fred,
 
I like your simplified electrical diagram. I reached almost exactly = the=20 same solution in designing the power grid for our IV except I have 3 = alternators=20 and 3 batteries. Other than that...very similar, big Schotky diodes = feeding the=20 essential bus from 3 independent electrical systems and the avionics bus = powered=20 by two systems, both diode isolated and able to crosstie to the third. I = also=20 have iron gyros, and round airspeed and altimeter backup instruments. I = am no=20 longer young but I have managed to retain my stupidity. I=E2=80=99ve not = yet achieved=20 the level of intelligence and maturity that you have as I still have = aspirations=20 for trans Pacific (and worse, trans Antarctic) flights. Maybe = I=E2=80=99ll see you in OZ=20 one day.
 
Bill Harrelson
N5ZQ 320 1,950 hrs
N6ZQ  IV under construction
 
 
 
Sent: Thursday, August 04, 2011 9:30 AM
Subject: [LML] Fw: Re: Re-doing my panel - carefully = thinking=20 through failures
 
 
Brent has written much on this topic including "In my "Glazed = and=20 Confused" presentation on "Glass Cockpits" I say that flying an = aircraft=20 with a non-certified, non TSO'ed glass standby (Dynon et al) is = like=20 jumping out of an airplane with only your main parachute and your = standby=20 plan is the fact you are wearing real soft socks."
 
I concur. 
 
When I was young and stupid (not long ago) I had thoughts of = long=20 overwater (think trans-Pacific) flights.  I also have = experience with=20 failure modes assessment analysis (FMEA) which frequently shows up = failure=20 modes easily over looked.  After reviewing various electrical = and=20 instrument configurations I arrived at a system design which is = shown in=20 simplified form in the attached sketch.  It consists of two=20 alternators, two batteries, four busses, and a lot of = opportunities for=20 cross tie.  I use dual Chelton screens, with PFD off the = essential=20 buss (many sources of power), the MFD off of the avionics bus = (which has=20 many sources of power), and back up electric attitude  = indicator (on=20 essential buss), turn and bank (essential buss) and air speed and = altitude=20 indicators.
 
You show me the failure and I can show you the automated or = manual=20 work around.  And critical stuff is all double protected with = circuit=20 breakers and surge arresters (not shown).
 
But even this diagram is not as safe as it could = be. =20 What about something simple like: a battery relay decides to go=20 flotch?  (One already has done so.)  That causes a main = bus to=20 go south forcing you to a cross tie solution, not ideal.  So = not=20 shown are by-pass switches and fuses around the relay solenoids I = added=20 "just in case" to provide redundancy on all supply routes.
 
I have a mechanical and electrical fuel pump.  And I = have an=20 electronic ignition and a magneto.
 
Two of everything, independent power modes, independent = pathways,=20 cross connects, multiple layers of electrical spike and surge = protection=20 and independent and different principles of gyroscopic display = and =20 electrical power supply.  Now one begins to achieve = realistically=20 (and defensible) high levels of reliability.  
 
If I could only achieve the same with the pilot.
 
Fred Moreno
 


 
 

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