Today's Message Index:
----------------------
1. 01:43 AM - Re: Safe Wire Types (Bob Verwey)
2. 04:16 AM - Re: Safe Wire Types (BobsV35B@aol.com)
3. 05:41 AM - Re: Safe Wire Types (racerjerry)
4. 05:41 AM - Re: Safe Wire Types (Robert L. Nuckolls, III)
5. 06:54 AM - Re: Re: Safe Wire Types (Robert L. Nuckolls, III)
6. 08:12 AM - Re: Safe Wire Types (Stein Bruch)
7. 12:54 PM - wire safety (cardinalnsb)
Message 1
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| Subject: | Re: Safe Wire Types |
Not Bob III, but if you want to replace the wiring in a Bonanza be prepared
to strip the whole interior out. As a former A&P/IA, and current Bonanza
owner, the only issue with the wiring in my opinion, might be some of the
circuit breakers, switches and limit switches.
On the Beech forum over the past ten years I don't recall seeing to many
wiring issues that present a danger. The system might be regarded as old
school, but it works!
Bob Verwey
IO 470 A35 Bonanza ZU-DLW
On 6 August 2012 04:39, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> nuckolls.bob@aeroelectric.com**>
>
> At 05:37 PM 8/5/2012, you wrote:
>
> If you're building a new airplane, use TKT Boeing or maybe TKT Airbus. If
> you have to fly in something older, or something that doesn't have these
> types of wire, and something happens, blame your aviation safety advisor if
> you lose people.
>
> Hmmm . . . where does one purchase this wire?
>
> And I'm thinking of buying a 1960 Bonanza Debonair??????????
>
> How about it ol' Bob. Would you recommend the wire
> bundles be stripped out and replaced?
>
>
> Bob . . .
>
>
Message 2
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| Subject: | Re: Safe Wire Types |
Good Morning Bob, Bob and All,
I would not replace the wiring unless it showed evidence of unintended
motion., but would carefully check all of the grounds and check for voltage
drop across any suspect CBs and switches.
Happy Skies,
Old Bob
PS Good to be able to meet you in RFD. Wish we could have talked a bit
more.
In a message dated 8/6/2012 3:44:31 A.M. Central Daylight Time,
bob.verwey@gmail.com writes:
And I'm thinking of buying a 1960 Bonanza Debonair??????????
How about it ol' Bob. Would you recommend the wire
bundles be stripped out and replaced?
Bob . . .
Message 3
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| Subject: | Re: Safe Wire Types |
I cannot argue with anything that has been said here; however, the real problem
lies at the ends of the wire.
If you hook up your new Taiwan audio gadget with 20 feet of 24 AWG and connect
it to a convenient 30 amp circuit breaker, you could find yourself in a would
of hurt if the device decides to short out. The breaker will never trip and the
wire will become a smoke generator. Ask me how I know.
Common hook-up wire purchased at your local electronics or auto parts store that
has PVC insulation will get things over with quicker.
Fortunately, my experience was in a service truck and not in a confined RV cockpit
at altitude. By the time I could get the truck stopped at the side of the
road, I was totally helpless and on the ground choking.
--------
Jerry King
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=380166#380166
Message 4
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| Subject: | Re: Safe Wire Types |
At 09:36 PM 8/5/2012, you wrote:
<nuckolls.bob@aeroelectric.com>
At 03:28 PM 8/5/2012, you wrote:
Ran across this link. Did some searching here to see if posted
previously, but that does not seem to be the case.
Anyone's thoughts on this?
http://www.vision.net.au/~apaterson/aviation/wire_types.htm
This tempest has been bubbling at various
vapor-generation rates for decades . . .
<SNIP>
I've worked some issues on Hawkers originally
certified with some exotic insulations that
would arc-track and experienced some electrical
events that did not precipitate a serious
accident. I'm aware of no incidents involving
electrical systems where Tefzel or pre-Tefzel
insulation was a factor. In other words, I
don't see the incident rates going down because
the insulation on the wire is Part 25 qualified.
I dug around in the archives and found some
of my data and reports generated therefrom for
the Hawker incidents cited.
Emacs!
Emacs!
Note that damage to these bundles ORIGINATED with
a single, small fault to ground. A contaminated
crack or more probably, rubbed through by motion
against the airframe. Note that this insulation
is a tape WRAPPED around the wires and fused
. . . not extruded as a contiguous amorphous
sheath.
Further, while these materials passed some form
of qualification testing at the time the airplane
was being designed, there was no investigation
as to behaviors under excitation for temperatures
produced by an electric arc that would trigger
a previously unconsidered form of propagation
for combustion . . . now called "arc tracking."
A fault in a single wire propagated catastrophic
damage to a bundle of wires (but did not set
the airplane on fire). The answer for these
airplanes is a new breaker (VERY expensive) that
can detect both hard faults (shorts and overloads)
and soft faults (arcing). Swissair 111 would probably
not have suffered its fate had the faulted wire
bundles not been routed adjacent to flammable
insulation.
Does anyone have flammable insulation in their
RV?
One cannot know the thinking behind selection
of this wire 30+ years ago. The military and
commercial aviation communities were wrestling
with some perceived shortfalls in the insulation
of choice for the era and the new kids on the
block . . . Teflon and cousins showed a lot of
promise.
Some folks made some terrible, expensive choices.
Don't know how many accidents were caused but
I do know of entire fleets of military aircraft
that were totally re-wired after carrier
based versions contracted dandruff of the
wire bundle and started shedding insulation
in little flakes.
I was working with the Gates-Piaggio GP-180 at
the time Lear was looking hard at Tefzel. An
export controlled product with strong military
implications. I was ready to go with RayChem's
Spec 55 wire with very nearly the same properties
of Tefzel and not export controlled . . . but
about 10-15% more expensive.
We ultimately acquired the export license and
the GP-180 was wired in Tefzel . . . and probably
still is. If it's not wired in Tefzel, then the
machine has probably fallen victim to knee-jerk
reactions so common to bombardment by Chicken
Little worriers without regard to assessment of
real risk.
Too many designers, regulators and decision makers for
modern products are NOT cognizant of history nor are
they capable of accurate consideration for magnitude
of risk. Their charter is to drive all risks to zero
no matter how much it costs.
Instead they float with the tide of regulations and
recommendations that flow from a constellation of
agencies who are paid to worry . . . and worry
they do. Present trends plotted into the future
suggest that risks associated with all forms of
transportation will be driven to ZERO. It's easy.
Regulate those systems out of existence with
constrictions of critical components like fuel,
unattainable efficiency mandates, traffic flow
boondoggles and yes . . . insulation on wires.
Bob . . .
Message 5
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| Subject: | Re: Safe Wire Types |
At 07:40 AM 8/6/2012, you wrote:
<gki@suffolk.lib.ny.us>
I cannot argue with anything that has been said
here; however, the real problem lies at the ends of the wire.
If you hook up your new Taiwan audio gadget with
20 feet of 24 AWG and connect it to a
=9Cconvenient=9D 30 amp circuit breaker, you
could find yourself in a would of hurt if the
device decides to short out. The breaker will
never trip and the wire will become a smoke generator. Ask me how I know.
Common hook-up wire purchased at your local
electronics or auto parts store that has PVC
insulation will get things over with quicker.
Fortunately, my experience was in a service truck
and not in a confined RV cockpit at altitude. By
the time I could get the truck stopped at the
side of the road, I was totally helpless and on the ground choking.
--------
Jerry King
Sure. This is why it's important not to loose
sight of the whole system by getting distracted
with features of one component. Breakers will do
their job to keep a wire from burning ASSUMING it
is properly sized to the task. Blaming the cloud
of noxious smoke on PVC is rather far down the
chain of events.
I doubt that the wreckage of Swissair 111 produced
THE wire that some have hypothesized to have
ignited nearby insulation. The crew didn't succumb
to a damaged wire that did not enjoy protection from
soft faults, it was smoke that was a byproduct of
another shortfall in selection and installation of
materials. This report speaks to dozens of incidents
involving "failures within the entertainment systems"
http://tinyurl.com/d6rgttp
but without implicating Tefzel failures as root
cause. It was Paterson's statement:
"Tefzel was found in Swiss Air flight SR111's
Inflight Entertainment System (IFEN) which was
suspected as being the cause of the inflight fire
and subsequent crash of the aircraft off Nova Scotia in November 1998."
Well duh . . . how does insulation on hookup wire
figure into the failures within components of
the in-flight entertainment system?
Even if there WAS a faulted wire, had the poor
choice of insulation not been present, the airplane
might have simply suffered wire bundle damage like
the Hawkers.
The lessons to be studied here go to the notion
that all accidents are propagated on a string
of conditions that follow a triggering event.
It's useful to consider the cost-benefit-risk-
ratios for eliminating the triggering event but
foolish to not include contributing conditions
as well. All of these accidents would have been
stopped by breaking the chain anywhere. If the
Swissair 111 incident had not ended sadly, this
statement from Airbus would have been humorous:
"Airbus spokeswoman Mary Anne Greczyn says the
company has rigorous standards for entertainment
and other aircraft systems. Airbus provides extra
protection on entertainment system wiring by
using sleeves and other materials, she says."
Protection of wires using sleeves . . . what's up
with that? Are the entertainment system wires worthy
of special attention not enjoyed by the rest of the
wiring in the airplane? Had the folks who first smelled
the impending failures been old TV technicians, perhaps
their learned sense of smell would have identified first-
failure as a capacitor, a resistor or burning ECB
material. At no place in any article have I found that
Tefzel wire . . . or any other wire is directly responsible
for triggering this incident. Yet we see statements
like . . .
The aviation industry has been grappling for
years with problems of cracked and deteriorated
wiring causing fires and emergency landings, he
says. Adding four miles of entertainment system
wire to a jet that may have more than 100 miles
of other wires is "like throwing gas on a fire."
Lacey believes planes are safer without the
systems. "We could choose to do without fancy
entertainment systems," he says. "A good book works for me."
Fine examples of Chicken Little journalism and
arm-chair, bureaucratic accident analysis. I've not
seen any direct evidence that this incident (or
dozens of others) would have been prevented by
replacing the Tefzel wire . . .
Tens of thousands of airplanes are flying with
PVC insulated wires . . . many of which are fed
by appropriately sized breakers that performed
as advertised and opened up without so much as
melting the insulation much less setting it on fire.
Bob . . .
Message 6
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Total waste of time to try and even acquire much less use that wire on a
small piston single plane. Wires in our planes are not carrying high Hz AC
voltage like the heavy iron I used to work with. As Bob has said
repeatedly, stick with regular Tefzel and you'll be golden. Yes there is
that one guy that has the one website that has been out there forever
written by a person with subjective personal and political motivation, and
some of the info is dubious (some of it is outright conjecture) to begin
with and also much of it doesn't apply to systems in our planes. Just
because someone put something on a webpage somewhere sometime and claims to
be an expert does not make it so. Stick with what works well for your
installation and don't try to turn your plane into a Boeing!
Just my 2 cents as usual.
Cheers,
Stein
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Marvin
Dorris Jr
Sent: Sunday, August 05, 2012 5:38 PM
Subject: RE: AeroElectric-List: Safe Wire Types
If you're building a new airplane, use TKT Boeing or maybe TKT Airbus. If
you have to fly in something older, or something that doesn't have these
types of wire, and something happens, blame your aviation safety advisor if
you lose people.
And I'm thinking of buying a 1960 Bonanza Debonair??????????
Best Regards to All,
> Subject: AeroElectric-List: Safe Wire Types
> From: jimhausch@gmail.com
> Date: Sun, 5 Aug 2012 13:28:56 -0700
> To: aeroelectric-list@matronics.com
>
>
> Ran across this link. Did some searching here to see if posted previously,
but that does not seem to be the case.
>
> Anyone's thoughts on this?
> http://www.vision.net.au/~apaterson/aviation/wire_types.htm
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=380111#380111
>
>
>
>
>
>
>=============
>
>
>
Message 7
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When I got my 1968 Cardinal, I considered "rewiring" with "new stuff", assuming
the "old stuff Cessna used" was inferior.
My (deceased) friend looked at it and laughed at me. He said it was fine (not
burned or cracked, pliable, etc.), and the problems I would create by the rewiring
greatly outweighed his assessment of any deficiency in the wiring. He started
in the business fixing mismatched wiring looms in new B52's, avionics install
type work in military aircraft, set the nuclear fuses in fighter bombers
("go down to the end of the runway and when you come back we will send the pilot
down to fly out"), and ended with a top secret conning tower clearance in
ballistic missile subs as field engineer.
I figured he knew a lot about safe wire, so I just kept the old Cessna wiring...
Skip Simpson
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