X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 10 Aug 2011 08:13:28 -0400 Message-ID: X-Original-Return-Path: Received: from imr-da06.mx.aol.com ([205.188.169.203] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5086769 for lml@lancaironline.net; Tue, 09 Aug 2011 09:37:46 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.169.203; envelope-from=VTAILJEFF@aol.com Received: from imo-da04.mx.aol.com (imo-da04.mx.aol.com [205.188.169.202]) by imr-da06.mx.aol.com (8.14.1/8.14.1) with ESMTP id p79Db5Mq028932 for ; Tue, 9 Aug 2011 09:37:05 -0400 Received: from VTAILJEFF@aol.com by imo-da04.mx.aol.com (mail_out_v42.9.) id q.1268.43281d9 (44048) for ; Tue, 9 Aug 2011 09:37:01 -0400 (EDT) Received: from smtprly-de03.mx.aol.com (smtprly-de03.mx.aol.com [205.188.249.170]) by cia-dd07.mx.aol.com (v129.10) with ESMTP id MAILCIADD074-b28a4e4137f9137; Tue, 09 Aug 2011 09:37:00 -0400 Received: from webmail-m003 (webmail-m003.sim.aol.com [64.12.101.86]) by smtprly-de03.mx.aol.com (v129.10) with ESMTP id MAILSMTPRLYDE038-b28a4e4137f9137; Tue, 09 Aug 2011 09:36:57 -0400 References: X-Original-To: lml@lancaironline.net Subject: Re: [LML] EFIS "Failure" X-Original-Date: Tue, 09 Aug 2011 09:36:57 -0400 X-AOL-IP: 75.49.225.118 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: vtailjeff@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CE24B08B5951F3_F14_87762_webmail-m003.sysops.aol.com" X-Mailer: AOL Webmail 34007-STANDARD Received: from 75.49.225.118 by webmail-m003.sysops.aol.com (64.12.101.86) with HTTP (WebMailUI); Tue, 09 Aug 2011 09:36:57 -0400 X-Original-Message-Id: <8CE24B08B4B09AD-F14-398C4@webmail-m003.sysops.aol.com> X-Spam-Flag:NO X-AOL-SENDER: VTAILJEFF@aol.com ----------MB_8CE24B08B5951F3_F14_87762_webmail-m003.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="us-ascii" over Jackson Hole at 16,000' in IMC.... -----Original Message----- From: Brent Regan To: lml@lancaironline.net Sent: Mon, Aug 8, 2011 8:40 pm Subject: [LML] EFIS "Failure" When we create the conformal document set (drawings, specifications, etc.)= for certified hardware we try to lock down every aspect of the design so= that vendors do not "improve" a component and cause an unforeseen problem= . One man's improvement can be another man's nightmare. Case in point.=20 =20 A friend with a Chelton IDU-I manufactured about 10 years ago (by Sierra= Flight Systems in Boise) was having a problem where the display would int= ermittently lose vertical synchronization and start flipping. I disassembl= ed the unit to find the problem. It seems the LCD display vendor, Panelvie= w, who also added the Anti Reflection (AR) coating, decided to add a metal= ized sticker to the display. Seems innocent enough, right? Well, with time= and temperature cycles the sticker started to peal and came in contact wi= th the backside of an inter-board connector that happened to be carrying= the V-SYNC signal. With heat and vibration the aluminum layer of the stic= ker was exposed and shorted the signal pins. The attached pictures clearly= show where the pins rubbed on the sticker.=20 =20 A freaking sticker?!?!?! Really?!?!?! That is one for the books.=20 =20 It is not the known knowns that get you. It is rarely the known unknowns= that get you. It is the unknown unknowns that get you.=20 =20 It is experiences like this that are the basis for my advice that, despite= your best efforts, sooner or later it may all go very wrong. And not for= a big obvious reason but for a stupid little tiny sticker of a reason. As= k your self now, in the comfort of your office chair, what is your plan fo= r when it does go very wrong?=20 =20 Regards=20 Brent Regan=20 -- or archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html ----------MB_8CE24B08B5951F3_F14_87762_webmail-m003.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="us-ascii" over Jackson Hole at 16,00= 0' in IMC....



-----Original Message-----
From: Brent Regan <brent@regandesigns.com>
To: lml@lancaironline.net
Sent: Mon, Aug 8, 2011 8:40 pm
Subject: [LML] EFIS "Failure"

When we create the conformal document= set (drawings, specifications, etc.) for certified hardware we try to loc= k down every aspect of the design so that vendors do not "improve" a compo= nent and cause an unforeseen problem. One man's improvement can be another= man's nightmare. Case in point. 
 
A friend with a Chelton IDU-I manufactured about 10 years ago (by Sierra= Flight Systems in Boise) was having a problem where the display would int= ermittently lose vertical synchronization and start flipping. I disassembl= ed the unit to find the problem. It seems the LCD display vendor, Panelvie= w, who also added the Anti Reflection (AR) coating, decided to add a metal= ized sticker to the display. Seems innocent enough, right? Well, with time= and temperature cycles the sticker started to peal and came in contact wi= th the backside of an inter-board connector that happened to be carrying= the V-SYNC signal. With heat and vibration the aluminum layer of the stic= ker was exposed and shorted the signal pins. The attached pictures clearly= show where the pins rubbed on the sticker. 
 
A freaking sticker?!?!?! Really?!?!?! That is one for the books. 
 
It is not the known knowns that get you. It is rarely the known unknowns= that get you. It is the unknown unknowns that get you. 
 
It is experiences like this that are the basis for my advice that, despite= your best efforts, sooner or later it may all go very wrong. And not for= a big obvious reason but for a stupid little tiny sticker of a reason. As= k your self now, in the comfort of your office chair, what is your plan fo= r when it does go very wrong? 
 
Regards 
Brent Regan 

 ----------MB_8CE24B08B5951F3_F14_87762_webmail-m003.sysops.aol.com--