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
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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
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| Subject: | Re: 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
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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 <dlj04@josephson.com> 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
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