---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 01/16/15: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:16 AM - Re: ASTM F2245 (David Josephson) 2. 09:54 AM - Re: ASTM F2245 et al (Robert L. Nuckolls, III) 3. 10:45 AM - Re: Re: ASTM F2245 (Jeff Luckey) ________________________________ Message 1 _____________________________________ Time: 08:16:48 AM PST US From: David Josephson Subject: AeroElectric-List: Re: ASTM F2245 Bob Nuckolls responded to my post > For $75 a year you can join ASTM and get all of the standards that > apply to aviation for free (you want ASTM volume 15 with your > membership.) And, you're then welcome to join the deliberation on > what they should include. End-users and other interested people are > Excellent point . . . I'll do that. I'll also > write to suggest that non-for profit distribution > should be allowed . . . You might consider instead writing a summary of the current standard without the legalese. It will be both more useful and less threatening to the legal beagles. > > Like RTCA, ASTM is at risk for becoming 'siloed' . . . > relatively isolated from accurate and useful > feedback from the very folks who would are supposed > to "benefit" by the best of what the specs have to offer > . . . and like the EAA feedback into AC43-13 many > years ago . . . a conduit for refinement. That's right. I should also point out that the 2007 version of the standard that's on the recreationalflying download site is quite different from the current one. And, this very issue of circuit protective devices has just been worked on, and is the subject of a ballot in F37.20 which closes on January 30. There is still some argument about the language, so I expect at least one more round of discussion before it's done, and the time is right now to propose alternate wording. ASTM, like most standards bodies, requires "the absence of sustained objection" to new standards language, or has to show a thorough review about why an objection is technically not valid. As proposed now, circuit overload protection must be installed on each circuit containing wiring rated for less than the combined output of the battery and alternator, must open before the conductor emits smoke, must not automatically reset, and must be accessible to and in clear view of the pilot if it covers required equipment, equipment essential to safety of flight unless redundant equipment is provided, or switchable circuit protection installed to accommodate aircraft operating procedures (combined switch/breaker). So a fusible link (not accessible in flight) to protect wiring to the starter would be OK unless the manufacturer decided that in-flight starter operation was essential. David Josephson ________________________________ Message 2 _____________________________________ Time: 09:54:55 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: ASTM F2245 et al >I would be more than happy to split this cost of membership, for >Bob, with anyone interested. We have received many times more than >this in experience and great advice. I am sure you will be a great >knowledgeable outspoken advocate for the OBAM community. > >Anyone interested, let us know here and we can easily make a >contribution through Paypal. > >Roger Roger, thanks but that's not necessary. I've got a 'budget' for professional expenses that includes memberships and the like. In fact, I purchased a copy of the document without knowing that for a few $ more, I could have had the membership + the document! In a few hours I'll be pitching about $150 worth of proof of concept ECBs that were ordered to do beta-assemblies on some new products. Yeah, those dollars might have bought me some new goodies but the 'sacrifice' greatly improved the quality of my work product. It's that cost-of-doing-business thingy . . . I'll look into a cooperative involvement with the LSA specs effort. Bob . . . ________________________________ Message 3 _____________________________________ Time: 10:45:15 AM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: Re: ASTM F2245 Boy this is all very interesting and wierd coincidence on the timing. I have a few thoughts: 1. I am a firm believer in protecting feeders. I would rather blow a fuse/current limiter that I can't reset in flight, than catch on fire. Absolutely no question about it. If I had an electrically dependent engine, and was dumb enough not to have redundant power, I would rather be flying a glider than a glider that is on fire. This idea seems obvious to me. And the recent posting re the RV-12 fire reinforces this idea. 2. After reviewing F2245 it seems strange that not only is such circuit protection not recommended but it is specifically prohibited. Seems like adding insult to injury. It must be due to the fact that small GA does not protect this feeder - but I don't believe that protection of this wire is specifically prohibited by the FARs. 3. Now, as BobN has informed us, the GA manufacturers decided a long time ago that protection was not necessary for this feeder. I sure would like to talk to someone who was in the room when that decision was made. I would like to know the thought process & what criteria was being considered. And if BobN does not know who these people were/are, then I don't know who would. I'm guessing that they came to a logical conclusion based on the criteria and context of the moment. But without know some of that context, it is difficult to understand. 4. In all other disciplines of electrical engineering (and I've worked on everything from Motor Homes to Mega-yachts, commercial & residential electrical contracting, etc.) there are codes, regulations, guidelines, or just plain old best practices that prohibit un-protected feeders. Why did the aviation community decide not to protect this particular wire? Just trying to get a little smarter... -Jeff On Friday, January 16, 2015 8:27 AM, David Josephson wrote: Bob Nuckolls responded to my post > For $75 a year you can join ASTM and get all of the standards that > apply to aviation for free (you want ASTM volume 15 with your > membership.) And, you're then welcome to join the deliberation on > what they should include. End-users and other interested people are > Excellent point . . . I'll do that. I'll also > write to suggest that non-for profit distribution > should be allowed . . . You might consider instead writing a summary of the current standard without the legalese. It will be both more useful and less threatening to the legal beagles. > > Like RTCA, ASTM is at risk for becoming 'siloed' . . . > relatively isolated from accurate and useful > feedback from the very folks who would are supposed > to "benefit" by the best of what the specs have to offer > . . . and like the EAA feedback into AC43-13 many > years ago . . . a conduit for refinement. That's right. I should also point out that the 2007 version of the standard that's on the recreationalflying download site is quite different from the current one. And, this very issue of circuit protective devices has just been worked on, and is the subject of a ballot in F37.20 which closes on January 30. There is still some argument about the language, so I expect at least one more round of discussion before it's done, and the time is right now to propose alternate wording. ASTM, like most standards bodies, requires "the absence of sustained objection" to new standards language, or has to show a thorough review about why an objection is technically not valid. As proposed now, circuit overload protection must be installed on each circuit containing wiring rated for less than the combined output of the battery and alternator, must open before the conductor emits smoke, must not automatically reset, and must be accessible to and in clear view of the pilot if it covers required equipment, equipment essential to safety of flight unless redundant equipment is provided, or switchable circuit protection installed to accommodate aircraft operating procedures (combined switch/breaker). So a fusible link (not accessible in flight) to protect wiring to the starter would be OK unless the manufacturer decided that in-flight starter operation was essential. David Josephson ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.