X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 27 Dec 2007 21:46:38 -0500 Message-ID: X-Original-Return-Path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123] verified) by logan.com (CommuniGate Pro SMTP 5.2c4) with ESMTP id 2621502 for lml@lancaironline.net; Thu, 27 Dec 2007 14:20:33 -0500 Received-SPF: none receiver=logan.com; client-ip=71.74.56.123; envelope-from=schaefer@rts-services.com Received: from Master.RTS-Services.com ([70.113.90.126]) by hrndva-omta04.mail.rr.com with ESMTP id <20071227191952.LBDB17668.hrndva-omta04.mail.rr.com@Master.RTS-Services.com> for ; Thu, 27 Dec 2007 19:19:52 +0000 Received: from RTSLaptop (cpe-76-189-112-182.neo.res.rr.com [76.189.112.182]) (authenticated bits=0) by Master.RTS-Services.com (8.13.1/8.13.1) with ESMTP id lBRJGcRB014329 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NO) for ; Thu, 27 Dec 2007 13:16:39 -0600 From: "Richard T. Schaefer" X-Original-To: "'Lancair Mailing List'" Subject: RE: [LML] Re: Imagination X-Original-Date: Thu, 27 Dec 2007 14:19:46 -0500 X-Original-Message-ID: <008101c848bd$72c48640$6601a8c0@RTSLaptop> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0082_01C84893.89EE7E40" X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 In-Reply-To: Thread-index: AchIkiE7hA/tWL+MShmRk+KrOz6eRAAJdxug X-Spam-Score: -1.332 () BAYES_00,DYN_RDNS_SHORT_HELO_HTML,HTML_MESSAGE,RDNS_DYNAMIC X-Scanned-By: MIMEDefang 2.58 on 192.168.10.101 This is a multi-part message in MIME format. ------=_NextPart_000_0082_01C84893.89EE7E40 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit _____ On the other hand, to hold that an all electronic system has as favorable probability numbers as electronic plus mechanical backup is not a matter of personal comfort level. It's just not a correct statement of the facts. Colyn, This statement can very well be true or false. You must always evaluate failures as a system. Identify where failures can happen and confirm that you have a backup and/or can LIVE with the failure. I could easily IMAGINE scenarios where an aircraft with an electrically dependent engine and mechanical gauges is more likely to have serious risk mitigation problems then an aircraft with a non electrically dependent engine and only electrical instruments. You can have a false sense of security if, for example, some of your mechanical devices are electrically dependent and your failure mode takes out it's electrical source. Vacuum systems are far more likely to fail than non vacuum systems. So when you really need them there is more likely a probability they may have their own failures. An all electric backup, that has no system coupling to the primary systems (i.e. independent power, transducers, wire harness, connectors, etc.) can be as reliable in a "System" context to those systems that you IMAGINE with mechanical backups. ------=_NextPart_000_0082_01C84893.89EE7E40 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

On the other hand, = to hold that an all electronic system has as favorable probability numbers as = electronic plus mechanical backup is not a matter of personal comfort level.  = It's just not a correct statement of the facts.

 

Colyn, This statement can very well be true or = false.

You must always evaluate failures as a system. = Identify where failures can happen and confirm that you have a backup and/or can = LIVE with the failure.

 

I could easily IMAGINE scenarios where an aircraft = with an electrically dependent engine and mechanical gauges is more likely to = have serious risk mitigation problems then an aircraft with a non electrically = dependent engine and only electrical instruments. =

 

You can have a false sense of security if, for = example, some of your mechanical devices are electrically dependent and your failure = mode takes out it’s electrical source. =

 

Vacuum systems are far more likely to fail than non = vacuum systems. So when you really need them there is more likely a probability = they may have their own failures.  

 

An all electric backup, that has no system coupling = to the primary systems (i.e. independent power, transducers, wire harness, = connectors, etc.) can be as reliable in a “System” context to those = systems that you IMAGINE with mechanical backups. =  

 

 

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