Today's Message Index:
----------------------
1. 05:47 AM - Re: Re: Why can't the tower hear me? (Dale Ensing)
2. 06:30 AM - Re: Re: Why can't the tower hear me? (Robert L. Nuckolls, III)
3. 06:52 AM - Re: Transpo V1200 regulator (Robert L. Nuckolls, III)
4. 09:02 AM - Article from AOPA on Glass EFIS failures (John Markey)
5. 09:02 AM - Article from AOPA on Glass EFIS failures (John Markey)
6. 11:58 AM - Re: Article from AOPA on Glass EFIS failures (Robert L. Nuckolls, III)
7. 12:04 PM - Charging a low battery (paul wilson)
8. 12:12 PM - Re: Article from AOPA on Glass EFIS failures (Robert Feldtman)
9. 12:44 PM - Re: Article from AOPA on Glass EFIS failures (Hinde, Frank George (Corvallis))
10. 02:24 PM - Re: Article from AOPA on Glass EFIS failures (Richard Girard)
11. 04:07 PM - Re: Charging a low battery (Matt Prather)
12. 07:01 PM - Re: Article from AOPA on Glass EFIS failures (luckymacy@comcast.net (lucky))
13. 07:19 PM - Re: Article from AOPA on Glass EFIS failures (Tim Lewis)
14. 07:45 PM - Re: Article from AOPA on Glass EFIS failures (George Braly)
15. 08:27 PM - Re: Charging a low battery (Ernest Christley)
Message 1
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Subject: | Re: RE: Why can't the tower hear me? |
No engine driven alternator or generator? How do you keep the battery charg
ed?
Dale Ensing
----- Original Message -----
From: Steve Ruse
To: aeroelectric-list@matronics.com
Sent: Sunday, August 03, 2008 10:26 PM
Subject: Re: AeroElectric-List: RE: Why can't the tower hear me?
My plane actually has no engine driven electrical system, just a 12v batt
ery that runs the radio, intercom and GPS. My wires are all shielded (incl
uding plug wires), and the plane has almost no electronics so noise sources
are minimal.
Message 2
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Subject: | Re: RE: Why can't the tower hear me? |
At 09:26 PM 8/3/2008 -0500, you wrote:
>My plane actually has no engine driven electrical system, just a 12v
>battery that runs the radio, intercom and GPS. My wires are all shielded
>(including plug wires), and the plane has almost no electronics so noise
>sources are minimal.
>
>Today, I did another test that sheds a lot of light on the
>situation. From 2,500', I called the tower from less than 6 miles
>out. My friend in his plane a few miles away reported that he could hear
>me loud and clear, but the tower said I was garbled and unreadable. To
>me, that indicates that some combination of factors between my radio and
>theirs is causing problems. At what point should I try to address it with
>them? I doubt they will care about my problem if no one else is having
>problems.
It's been suggested that you try another hand-held on the same antenna.
Also, while still on the field you might try using the "rubber-ducky"
antenna that comes with the radio. It would also be interesting to have
a friend visit the tower (a gray-haired ol' ham operator that used to
build his own stuff would be good) and see what your signal sounds like
to him while you switch between the rubber duck, the ship's antenna and
perhaps even another hand-held on its own rubber duck and the ship's
antenna.
I recall a trip to the practice area early one morning before I
got my ticket. Some guy in a Pacer called the tower and was truly
garbled to the point that I could barely understand him in the airplane.
However, the tower guys could understand him better than I could from
the quieter tower cab . . . they handled him like any other traffic.
I was amazed that they did not at least suggest he have his radio
looked at (I'll bet his REAL carbon mic was going bad). By the time
I got back from the practice area, the guy had refueled and gone
or I would have approached him. In fact, I cannot recall any time
hearing a traffic controller complain about signals that I thought
sucked for air. It's only when the pilot specifically asked about
his radio that anyone offered much of an opinion and for the most
part, controllers were exceedingly generous in their assessments.
Years ago it was not uncommon for a multi-channel radio to
have problems on every tenth step in the progression of frequency
selections when one frequency control crystal of several dozen
had gone bad. Modern radios use one crystal to stabilize a digital
frequency synthesizer so if one frequency is off, ALL frequencies
are off too. A quick check of your radio against a counter would
be good. Any two-way radio shop in your area could do this test
in about ten seconds.
It's just possible that someone in the tower has a "thing" for
you or your homebuilt . . . I've come to understand that the
bell-curve is a fact of nature . . . it cannot be ignored. For
every Mother Theresa there's GOT to be a Saddam Hussein.
The best way to resolve the true nature of your difficulties
is to get a third party involved . . . someone experienced in
judging the quality of radio signals.
If your third party approaches the tower folks with the notion
that you need to conduct an experiment to resolve a problem
they'd be hard pressed not to cooperate. Do a double-blind
study of the four conditions I suggested above with your radio
and one other radio and two different antennas. Just speak to
condition A, B, C and D without letting anyone at the other
end know what the details of any particular condition.
Bob . . .
Message 3
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Subject: | Transpo V1200 regulator |
At 11:02 AM 8/2/2008 -0500, you wrote:
>Okay, I spent a little time poking around with the harness that came with
>the regulator - high output alternator and attached is what I found, does
>this help at all ? or just ask more questions ?
>It looks like I and A are tied together from the main output terminal of the
>alternator !
>
>NOTE: the relay CAME with the harness and I am told the on off for the relay
>is from the ignition circuit or switch.
It appears that your regulator came with a companion alternator.
It also appears that the previous installer went inside the
alternator to ADD a leadwire for the "S" terminal. Most of
regulators with the I, A, S, F terminal sets run well when
wired as shown for the "ford" regulator in Z-11.
For your installation, the wire off the relay would go to
directly to your field supply breaker or fuse. The wire to "+12v
ignition" would go to the downstream side of the alternator
control switch. See:
http://www.aeroelectric.com/_temp/Skiba_VR1200_Wiring.jpg
>My main concern is why they took power into I and A from the main output of
>the alternator with no fuse or wire protection ? and how do I tie this into
>the Z figures??
In the good old days, the "I" terminal was an open collector,
transistor pull-down that would not tolerate being wired
as shown. If the bus was hot and the engine not running, then
the "I" terminal current expecting to illuminate a bulb would
be too high and the transistor would be damaged. It may be that
modern equivalents of this design
>Same as below ?
>This unit is suppose to have OV protection and all that so No crow bar is
>required.
It would be interesting to know the details of the advertised
OV protection. Many automotive devices where I've been privileged
to see real schematics offered only OV warning by lighting the
fault light. It did not shut down the regulator. Further, if
the failure was due to some fault on the regulator chip itself,
most design goals would be wary of letting a chip monitor itself.
Unfortunately, the folks who sell these devices tend to be
cognizant only of those words that are offered on the advertising
literature and installation instructions. So, if the data
say "OV protected" what else would you want to know? I'd
like to see the schematics before I hung my hat on their
OV protection peg.
There are dozens of independent, OV protection devices for
alternators who's design goals are quite clear and their
functionality assured. I don't know enough about the V1200
to offer any advice one way or another.
In any case, wired as shown in the drawing cited above should
get it up and running.
Bob . . .
Message 4
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Subject: | Article from AOPA on Glass EFIS failures |
Article worth forwarding to this list from AOPA
-
-
July 30, 2008 by Bruce Landsberg , AOPA Safety blog
The old joke about the fully automated airliner with no flight crew --jus
t an automated cabin announcement that misfires --seems prophetic with la
st week=92s NTSB announcement about massive display failure on Airbus aircr
aft. There were 49 failures on Airbus 319 and 320 aircraft including seven
incidents where all six screens failed simultaneously. Didn=92t think that
was possible? Neither did the manufacturer, the FAA or the NTSB.
As light GA manufacturers rush into glass cockpits, is it unseemly to ask w
hat assurance we have that there will not be a catastrophic failure or at l
east a significant failure in our less robust systems? Several years ago I
had the privilege of getting a demo in one of the early all-glass light air
craft which suffered a total flight display meltdown. It wasn=92t an issue
since we were in good VFR and there were backup instruments. Still, this is
n=92t what=92s supposed to happen.
After one flies enough and sees enough equipment break - some of it harmles
sly and some of it at the least opportune time --a sense of caution or pe
rhaps cynicism sets in. Duplication of hardware on critical things like com
m, nav and flight displays means less fancy footwork on the pilot=92s part
when something goes south.
I suspect the record keeping on Part 91 flights flown in light aircraft whe
n a flight display dies is not very accurate, even though NTSB Part 830 req
uires, somewhat vaguely, pilots to report the in-flight failure of electric
al systems that require =93sustained use of =85.backup power to =85retain f
light control or essential instruments.=94
Has anybody had, or know of someone who had, a major glass malfunction and
did it get reported and to whom? The purpose is not to rat out the manufact
urers but to insure that weak points get fixed before someone is hurt.
Bruce Landsberg
Executive Director, AOPA Air Safety Foundation
-
-
"One of the great mistakes is to judge policies and programs
- by their intentions rather than their results."- -Milton Friedman
-
-=0A=0A=0A
Message 5
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Subject: | Article from AOPA on Glass EFIS failures |
Article worth forwarding to this list from AOPA
-
-
July 30, 2008 by Bruce Landsberg , AOPA Safety blog
The old joke about the fully automated airliner with no flight crew --jus
t an automated cabin announcement that misfires --seems prophetic with la
st week=92s NTSB announcement about massive display failure on Airbus aircr
aft. There were 49 failures on Airbus 319 and 320 aircraft including seven
incidents where all six screens failed simultaneously. Didn=92t think that
was possible? Neither did the manufacturer, the FAA or the NTSB.
As light GA manufacturers rush into glass cockpits, is it unseemly to ask w
hat assurance we have that there will not be a catastrophic failure or at l
east a significant failure in our less robust systems? Several years ago I
had the privilege of getting a demo in one of the early all-glass light air
craft which suffered a total flight display meltdown. It wasn=92t an issue
since we were in good VFR and there were backup instruments. Still, this is
n=92t what=92s supposed to happen.
After one flies enough and sees enough equipment break - some of it harmles
sly and some of it at the least opportune time --a sense of caution or pe
rhaps cynicism sets in. Duplication of hardware on critical things like com
m, nav and flight displays means less fancy footwork on the pilot=92s part
when something goes south.
I suspect the record keeping on Part 91 flights flown in light aircraft whe
n a flight display dies is not very accurate, even though NTSB Part 830 req
uires, somewhat vaguely, pilots to report the in-flight failure of electric
al systems that require =93sustained use of =85.backup power to =85retain f
light control or essential instruments.=94
Has anybody had, or know of someone who had, a major glass malfunction and
did it get reported and to whom? The purpose is not to rat out the manufact
urers but to insure that weak points get fixed before someone is hurt.
Bruce Landsberg
Executive Director, AOPA Air Safety Foundation
-
-
"One of the great mistakes is to judge policies and programs
- by their intentions rather than their results."- -Milton Friedman
-
-=0A=0A=0A
Message 6
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Subject: | Re: Article from AOPA on Glass EFIS failures |
At 08:56 AM 8/4/2008 -0700, you wrote:
>Article worth forwarding to this list from AOPA
>
>
>July 30, 2008 by Bruce Landsberg , AOPA Safety blog<?xml:namespace prefix
>= o ns = "urn:schemas-microsoft-com:office:office" />
>The old joke about the fully automated airliner with no flight crew - just
>an automated cabin announcement that misfires - seems prophetic with last
>week's NTSB announcement about massive display failure on Airbus aircraft.
>There were 49 failures on Airbus 319 and 320 aircraft including seven
>incidents where all six screens failed simultaneously. Didn't think that
>was possible? Neither did the manufacturer, the FAA or the NTSB.
<snip>
>
>"One of the great mistakes is to judge policies and programs
> by their intentions rather than their results." -Milton Friedman
You betcha!
Has anyone found further discussions of these events on the Airbus?
I spent about 30 minutes searching the web . . . turned up a number
of items dealing with EFIS (or electrical system) failures on
various ATP class aircraft . . . but nothing that speaks to what
might be called an epidemic of failures aboard the Airbus.
I'm having trouble visualizing the lack of attention to system
design that produces gross failures of flight deck systems.
I cannot imagine folks who designed the A319/320 were so lacking
in due diligence.
How do these tales affect the OBAM aircraft community?
I'll suggest no more than ANY story of gross systems failure
aboard ANY vehicle. If it's important that failures do not
propagate across multiple systems, then it's generally not
difficult to make sure this doesn't happen.
I think I've mentioned this before . . . but if I were
building an airplane intended to spend a lot of time in
the clouds, I'd take advantage of the low cost, GPS aided
wing levelers and install TWO . . . each driven by its
own GPS engine (they're under $30 now). Further, I'd make
sure that each system was powered separately. If you have
even one of these devices working (along with alt and a/s)
there is nothing ATC asks you to do that cannot be
accomplished with no other instrumentation at all while
you maneuver to VMC somewhere.
As many of you have already decided, there are back-up
steam gages to your "non certified" glass displays.
We've discussed separation of duties between various energy
sources -AND- loads that are exceedingly useful when you
can't see the ground.
I'm still pained by narratives from incident investigations
where a single failure (perhaps combined with mis-positioning
of controls by crew) caused a cascade of failures or shutdowns
in otherwise perfectly good systems.
Z-14 is but one example of a way that one can build a firewall
between a catastrophic electrical event and the total suite
of necessary equipment items. Z-13/8 is a two-layer electrical
system that offers excellent robustness in the face of certain
failures.
There's a difference between how the TC side of the house
thinks and how we are permitted to think when it comes to
failure management. They bust their butts striving for
MTBF and reliability tree numbers that would make King
Midas envious. We're allowed to consider that EVERY part
in the system is going to quit at some point in time. If
it quits because we ignored simple preventative maintenance
duties and wore the thing out, then a pox on OUR house. If we
REALLY want it to work, it FAILS for unanticipated issues
and we didn't have a Plan-B . . . then it matters not
whether the thing had a 1,000 or 1,000,000 hour MTBF
number. Anyone who places any degree of faith in the
published reliability numbers for the purpose of keeping
his underwear dry has been poorly taught or wasn't paying
attention.
I don't intend to diminish the significance of anyone's
difficulties in the cockpit . . . especially those
responsible for hundreds of lives. I ride behind
a crew of those folks with some frequency. At the same
time, let us not assign significance to the miseries
handed down to our brothers by a regulatory
process that runs smoother on intentions than
upon cold logic. By virtue of understanding
you've acquired one can craft and meet design
goals that put you light-years away from the
probability of experiencing an electrical system
event that ruins your day.
Bob . . .
Message 7
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Subject: | Charging a low battery |
I think this has been discussed before, but I vaguely remember. Why
doesn't my truck blow the 30a fuse when I use it to charge my nearly
dead trailer batteries (less than 9v)? I have had to do this several
times and I just connect the truck to the trailer up start the engine
and rev it up. No ill effects to report and the fuse did not fail.
The truck has a 110a alternator and 2 size 65 batteries (diesel).
During this charging I see 13.8v or so on the cigar lighter plug.
Thanks, Paul
Message 8
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Subject: | Re: Article from AOPA on Glass EFIS failures |
The three letters "EMP" should strike fear in our flying (and driving)
hearts - I know, very remote, but some in the govt are planning for it.
bobf
On 8/4/08, Robert L. Nuckolls, III <nuckolls.bob@cox.net> wrote:
>
> nuckolls.bob@cox.net>
>
> At 08:56 AM 8/4/2008 -0700, you wrote:
>
>> Article worth forwarding to this list from AOPA
>>
>>
>>
>> July 30, 2008 by Bruce Landsberg , AOPA Safety blog<?xml:namespace prefix
>> = o ns = "urn:schemas-microsoft-com:office:office" />
>> The old joke about the fully automated airliner with no flight crew - just
>> an automated cabin announcement that misfires - seems prophetic with last
>> week's NTSB announcement about massive display failure on Airbus aircraft.
>> There were 49 failures on Airbus 319 and 320 aircraft including seven
>> incidents where all six screens failed simultaneously. Didn't think that was
>> possible? Neither did the manufacturer, the FAA or the NTSB.
>>
>
> <snip>
>
>>
>> "One of the great mistakes is to judge policies and programs
>> by their intentions rather than their results." -Milton Friedman
>>
>
> You betcha!
>
> Has anyone found further discussions of these events on the Airbus?
> I spent about 30 minutes searching the web . . . turned up a number
> of items dealing with EFIS (or electrical system) failures on
> various ATP class aircraft . . . but nothing that speaks to what
> might be called an epidemic of failures aboard the Airbus.
>
> I'm having trouble visualizing the lack of attention to system
> design that produces gross failures of flight deck systems.
> I cannot imagine folks who designed the A319/320 were so lacking
> in due diligence.
>
> How do these tales affect the OBAM aircraft community?
> I'll suggest no more than ANY story of gross systems failure
> aboard ANY vehicle. If it's important that failures do not
> propagate across multiple systems, then it's generally not
> difficult to make sure this doesn't happen.
>
> I think I've mentioned this before . . . but if I were
> building an airplane intended to spend a lot of time in
> the clouds, I'd take advantage of the low cost, GPS aided
> wing levelers and install TWO . . . each driven by its
> own GPS engine (they're under $30 now). Further, I'd make
> sure that each system was powered separately. If you have
> even one of these devices working (along with alt and a/s)
> there is nothing ATC asks you to do that cannot be
> accomplished with no other instrumentation at all while
> you maneuver to VMC somewhere.
>
> As many of you have already decided, there are back-up
> steam gages to your "non certified" glass displays.
> We've discussed separation of duties between various energy
> sources -AND- loads that are exceedingly useful when you
> can't see the ground.
>
> I'm still pained by narratives from incident investigations
> where a single failure (perhaps combined with mis-positioning
> of controls by crew) caused a cascade of failures or shutdowns
> in otherwise perfectly good systems.
>
> Z-14 is but one example of a way that one can build a firewall
> between a catastrophic electrical event and the total suite
> of necessary equipment items. Z-13/8 is a two-layer electrical
> system that offers excellent robustness in the face of certain
> failures.
>
> There's a difference between how the TC side of the house
> thinks and how we are permitted to think when it comes to
> failure management. They bust their butts striving for
> MTBF and reliability tree numbers that would make King
> Midas envious. We're allowed to consider that EVERY part
> in the system is going to quit at some point in time. If
> it quits because we ignored simple preventative maintenance
> duties and wore the thing out, then a pox on OUR house. If we
> REALLY want it to work, it FAILS for unanticipated issues
> and we didn't have a Plan-B . . . then it matters not
> whether the thing had a 1,000 or 1,000,000 hour MTBF
> number. Anyone who places any degree of faith in the
> published reliability numbers for the purpose of keeping
> his underwear dry has been poorly taught or wasn't paying
> attention.
>
> I don't intend to diminish the significance of anyone's
> difficulties in the cockpit . . . especially those
> responsible for hundreds of lives. I ride behind
> a crew of those folks with some frequency. At the same
> time, let us not assign significance to the miseries
> handed down to our brothers by a regulatory
> process that runs smoother on intentions than
> upon cold logic. By virtue of understanding
> you've acquired one can craft and meet design
> goals that put you light-years away from the
> probability of experiencing an electrical system
> event that ruins your day.
>
> Bob . . .
>
>
Message 9
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Subject: | Article from AOPA on Glass EFIS failures |
Amen Bob!..Plan for failure because it will happen.
As for me I fly behind a DYNON EFIS and have a Trutrak wingleveler..
During all of my practice approaches (and some real approaches) I fly my twitchy
RV by hand...I don't feel I need 2 winglevelers but I am certainly prepared
to hand fly it out of the clouds (or down to minimums) if have to..
To me the multiple failure scenario is unbelievable also.
Cheers
Frank
Electrically dependant RV7a
You betcha!
. By virtue of understanding
you've acquired one can craft and meet design
goals that put you light-years away from the
probability of experiencing an electrical system
event that ruins your day.
Bob . . .
Message 10
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Subject: | Re: Article from AOPA on Glass EFIS failures |
Bob, et al, Here's one possibility for failure while still on the ground, an
open or leaky canopy on a night of intense ground fog that lets the whole
aircraft cold soak and become coated with water.
Happened on my truck (an electrically dependant 2006 Toyota Tacoma Pre
Runner) which has eight on board computers. I left the windows down all
night and came out the next morning to find the interior soaked.
The engine started normally, but almost immediately the dash began to light
up like the proverbial Christmas tree. The stability control system, ABS
system, the electric limited slip differential, and the service engine
warning lamps were all lit. Brakes worked, as did the FBW throttle, although
applying the brakes caused the left turn signal to light, so I continued on
my way. After my first stop the lights were out after start up, then came
back on a mile or so down the road. After my second stop the lights were out
after start up and stayed out, although applying the brakes still caused the
left turn signal to light. It was on this leg of the trip that I learned
that actuating the left turn signal caused the cruise control to turn off.
Once we were well into the heat of the Kansas day, all the symptoms went
away.
I've put the truck through some pretty wild weather on many cross country
drives to both coasts and never saw any problems like this, but one good
soaking of the interior sure made for an interesting morning.
Rick
On Mon, Aug 4, 2008 at 2:40 PM, Hinde, Frank George (Corvallis) <
frank.hinde@hp.com> wrote:
> <frank.hinde@hp.com>
>
> Amen Bob!..Plan for failure because it will happen.
>
> As for me I fly behind a DYNON EFIS and have a Trutrak wingleveler..
>
> During all of my practice approaches (and some real approaches) I fly my
> twitchy RV by hand...I don't feel I need 2 winglevelers but I am certainly
> prepared to hand fly it out of the clouds (or down to minimums) if have to..
>
> To me the multiple failure scenario is unbelievable also.
>
> Cheers
>
> Frank
> Electrically dependant RV7a
>
> You betcha!
>
> . By virtue of understanding
> you've acquired one can craft and meet design
> goals that put you light-years away from the
> probability of experiencing an electrical system
> event that ruins your day.
>
> Bob . . .
>
>
Message 11
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Subject: | Re: Charging a low battery |
I think what's going on here is that it probably takes very little current
to raise the voltage on a dead battery from 9V to 14V - as long as no
cells are shorted. Once the cell voltage comes up, the current drawn
drops even further - small voltage difference between the alternator
output and the stacked cell voltage.
How much current the battery can take will also depend on the internal
resistance of its cells. It's possible that if you had batteries with
low(er) internal resistance (an RG type, maybe), you'd start blowing
fuses. Bob posted a note a while back about certain aircraft that had
charging system problems when running low internal resistance RG
batteries.
Your hi power alternator can be convinced to provide its full output if
you connect a load which will continue to drop the bus voltage.
Regards,
Matt-
>
> I think this has been discussed before, but I vaguely remember. Why
> doesn't my truck blow the 30a fuse when I use it to charge my nearly
> dead trailer batteries (less than 9v)? I have had to do this several
> times and I just connect the truck to the trailer up start the engine
> and rev it up. No ill effects to report and the fuse did not fail.
> The truck has a 110a alternator and 2 size 65 batteries (diesel).
> During this charging I see 13.8v or so on the cigar lighter plug.
> Thanks, Paul
>
>
Message 12
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Subject: | Re: Article from AOPA on Glass EFIS failures |
http://online.wsj.com/article/SB121684995725478651.html?mod=googlenews_wsj
-------------- Original message --------------
From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
>
>
> At 08:56 AM 8/4/2008 -0700, you wrote:
> >Article worth forwarding to this list from AOPA
> >
> >
> >
> >July 30, 2008 by Bruce Landsberg , AOPA Safety blog> >= o ns = "urn:schemas-microsoft-com:office:office"
/>
> >The old joke about the fully automated airliner with no flight crew - just
> >an automated cabin announcement that misfires - seems prophetic with last
> >week's NTSB announcement about massive display failure on Airbus aircraft.
> >There were 49 failures on Airbus 319 and 320 aircraft including seven
> >incidents where all six screens failed simultaneously. Didn't think that
> >was possible? Neither did the manufacturer, the FAA or the NTSB.
>
>
> >
> >"One of the great mistakes is to judge policies and programs
> > by their intentions rather than their results." -Milton Friedman
>
> You betcha!
>
> Has anyone found further discussions of these events on the Airbus?
> I spent about 30 minutes searching the web . . . turned up a number
> of items dealing with EFIS (or electrical system) failures on
> various ATP class aircraft . . . but nothing that speaks to what
> might be called an epidemic of failures aboard the Airbus.
>
> I'm having trouble visualizing the lack of attention to system
> design that produces gross failures of flight deck systems.
> I cannot imagine folks who designed the A319/320 were so lacking
> in due diligence.
>
> How do these tales affect the OBAM aircraft community?
> I'll suggest no more than ANY story of gross systems failure
> aboard ANY vehicle. If it's important that failures do not
> propagate across multiple systems, then it's generally not
> difficult to make sure this doesn't happen.
>
> I think I've mentioned this before . . . but if I were
> building an airplane intended to spend a lot of time in
> the clouds, I'd take advantage of the low cost, GPS aided
> wing levelers and install TWO . . . each driven by its
> own GPS engine (they're under $30 now). Further, I'd make
> sure that each system was powered separately. If you have
> even one of these devices working (along with alt and a/s)
> there is nothing ATC asks you to do that cannot be
> accomplished with no other instrumentation at all while
> you maneuver to VMC somewhere.
>
> As many of you have already decided, there are back-up
> steam gages to your "non certified" glass displays.
> We've discussed separation of duties between various energy
> sources -AND- loads that are exceedingly useful when you
> can't see the ground.
>
> I'm still pained by narratives from incident investigations
> where a single failure (perhaps combined with mis-positioning
> of controls by crew) caused a cascade of failures or shutdowns
> in otherwise perfectly good systems.
>
> Z-14 is but one example of a way that one can build a firewall
> between a catastrophic electrical event and the total suite
> of necessary equipment items. Z-13/8 is a two-layer electrical
> system that offers excellent robustness in the face of certain
> failures.
>
> There's a difference between how the TC side of the house
> thinks and how we are permitted to think when it comes to
> failure management. They bust their butts striving for
> MTBF and reliability tree numbers that would make King
> Midas envious. We're allowed to consider that EVERY part
> in the system is going to quit at some point in time. If
> it quits because we ignored simple preventative maintenance
> duties and wore the thing out, then a pox on OUR house. If we
> REALLY want it to work, it FAILS for unanticipated issues
> and we didn't have a Plan-B . . . then it matters not
> whether the thing had a 1,000 or 1,000,000 hour MTBF
> number. Anyone who places any degree of faith in the
> published reliability numbers for the purpose of keeping
> his underwear dry has been poorly taught or wasn't paying
> attention.
>
> I don't intend to diminish the significance of anyone's
> difficulties in the cockpit . . . especially those
> responsible for hundreds of lives. I ride behind
> a crew of those folks with some frequency. At the same
> time, let us not assign significance to the miseries
> handed down to our brothers by a regulatory
> process that runs smoother on intentions than
> upon cold logic. By virtue of understanding
> you've acquired one can craft and meet design
> goals that put you light-years away from the
> probability of experiencing an electrical system
> event that ruins your day.
>
> Bob . . .
>
>
>
>
>
<html><body>
<DIV><A href="http://online.wsj.com/article/SB121684995725478651.html?mod=googlenews_wsj">http://online.wsj.com/article/SB121684995725478651.html?mod=googlenews_wsj</A></DIV>
<DIV> </DIV>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px
solid">-------------- Original message -------------- <BR>From: "Robert L. Nuckolls,
III" <nuckolls.bob@cox.net> <BR><BR>> --> AeroElectric-List
message posted by: "Robert L. Nuckolls, III" <BR>> <NUCKOLLS.BOB@COX.NET><BR>>
<BR>> At 08:56 AM 8/4/2008 -0700, you wrote: <BR>> >Article
worth forwarding to this list from AOPA <BR>> > <BR>> > <BR>>
> <BR>> >July 30, 2008 by Bruce Landsberg , AOPA Safety blog> >=
o ns = "urn:schemas-microsoft-com:office:office" /> <BR>> >The old
joke about the fully automated airliner with no flight crew - just <BR>> >an
automated cabin announcement that misfires - seems prophetic with last <BR>>
>week's NTSB announcement about massive display failure on Airbus aircraft.
<BR>> >There were 49 failures on Airbus 319 and 320 aircraft including
seven <BR>> >incidents where all six scr
eens f
ailed simultaneously. Didn't think that <BR>> >was possible? Neither did
the manufacturer, the FAA or the NTSB. <BR>> <BR>> <SNIP><BR>> > <BR>>
>"One of the great mistakes is to judge policies and programs <BR>>
> by their intentions rather than their results." -Milton Friedman <BR>>
<BR>> You betcha! <BR>> <BR>> Has anyone found further discussions
of these events on the Airbus? <BR>> I spent about 30 minutes searching
the web . . . turned up a number <BR>> of items dealing with EFIS (or electrical
system) failures on <BR>> various ATP class aircraft . . . but nothing
that speaks to what <BR>> might be called an epidemic of failures aboard
the Airbus. <BR>> <BR>> I'm having trouble visualizing the lack of attention
to system <BR>> design that produces gross failures of flight deck systems.
<BR>> I cannot imagine folks who designed the A319/320 were so lacking
<BR>> in due diligence. <BR>> <BR>> How do
these
tales affect the OBAM aircraft community? <BR>> I'll suggest no more than ANY
story of gross systems failure <BR>> aboard ANY vehicle. If it's important
that failures do not <BR>> propagate across multiple systems, then it's
generally not <BR>> difficult to make sure this doesn't happen. <BR>> <BR>>
I think I've mentioned this before . . . but if I were <BR>> building
an airplane intended to spend a lot of time in <BR>> the clouds, I'd take
advantage of the low cost, GPS aided <BR>> wing levelers and install TWO .
. . each driven by its <BR>> own GPS engine (they're under $30 now). Further,
I'd make <BR>> sure that each system was powered separately. If you have
<BR>> even one of these devices working (along with alt and a/s) <BR>>
there is nothing ATC asks you to do that cannot be <BR>> accomplished with
no other instrumentation at all while <BR>> you maneuver to VMC somewhere.
<BR>> <BR>> As many of you have already decide
d, the
re are back-up <BR>> steam gages to your "non certified" glass displays. <BR>>
We've discussed separation of duties between various energy <BR>> sources
-AND- loads that are exceedingly useful when you <BR>> can't see the ground.
<BR>> <BR>> I'm still pained by narratives from incident investigations
<BR>> where a single failure (perhaps combined with mis-positioning
<BR>> of controls by crew) caused a cascade of failures or shutdowns <BR>>
in otherwise perfectly good systems. <BR>> <BR>> Z-14 is but one example
of a way that one can build a firewall <BR>> between a catastrophic electrical
event and the total suite <BR>> of necessary equipment items. Z-13/8
is a two-layer electrical <BR>> system that offers excellent robustness in
the face of certain <BR>> failures. <BR>> <BR>> There's a difference
between how the TC side of the house <BR>> thinks and how we are permitted
to think when it comes to <BR>> failure manageme
nt. Th
ey bust their butts striving for <BR>> MTBF and reliability tree numbers that
would make King <BR>> Midas envious. We're allowed to consider that EVERY
part <BR>> in the system is going to quit at some point in time. If <BR>>
it quits because we ignored simple preventative maintenance <BR>> duties
and wore the thing out, then a pox on OUR house. If we <BR>> REALLY want it
to work, it FAILS for unanticipated issues <BR>> and we didn't have a Plan-B
. . . then it matters not <BR>> whether the thing had a 1,000 or 1,000,000
hour MTBF <BR>> number. Anyone who places any degree of faith in the <BR>>
published reliability numbers for the purpose of keeping <BR>> his underwear
dry has been poorly taught or wasn't paying <BR>> attention. <BR>>
<BR>> I don't intend to diminish the significance of anyone's <BR>>
difficulties in the cockpit . . . especially those <BR>> responsible for hundreds
of lives. I ride behind <BR>> a crew of tho
se fol
=====
<pre><b><font size=2 color="#000000" face="courier new,courier">
</b></font></pre></body></html>
Message 13
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Subject: | Re: Article from AOPA on Glass EFIS failures |
This sort of thing is why my EFIS-equipped RV-10 (with electronic
ignition) is built with backup mechanical altimeter and airspeed, a
vacuum powered artificial horizon, and an old fashioned mag to back up
the electronic ignition. That's the most diverse approach to redundancy
I could get for my experimental aircraft.
An unanticipated event may be able to take out even a well designed
electrical bus that has passed multiple peer reviews (Diamond twin star,
for example), but it's pretty unlikely to take out the vacuum pump or
the mag at the same time.
--
Tim Lewis -- HEF (Manassas, VA)
RV-6A N47TD -- 1000 hrs
RV-10 #40059 under construction
John Markey wrote:
> Article worth forwarding to this list from AOPA
>
>
>
> July 30, 2008 by Bruce Landsberg , AOPA Safety blog
>
> The old joke about the fully automated airliner with no flight crew
> - just an automated cabin announcement that misfires - seems prophetic
> with last weeks NTSB announcement about massive display failure on
> Airbus aircraft. There were 49 failures on Airbus 319 and 320 aircraft
> including seven incidents where all six screens failed simultaneously.
> Didnt think that was possible? Neither did the manufacturer, the FAA
> or the NTSB.
> As light GA manufacturers rush into glass cockpits, is it unseemly to
> ask what assurance we have that there will not be a catastrophic
> failure or at least a significant failure in our less robust systems?
> Several years ago I had the privilege of getting a demo in one of the
> early all-glass light aircraft which suffered a total flight display
> meltdown. It wasnt an issue since we were in good VFR and there were
> backup instruments. Still, this isnt whats supposed to happen.
> After one flies enough and sees enough equipment break - some of it
> harmlessly and some of it at the least opportune time - a sense of
> caution or perhaps cynicism sets in. Duplication of hardware on
> critical things like comm, nav and flight displays means less fancy
> footwork on the pilots part when something goes south.
> I suspect the record keeping on Part 91 flights flown in light
> aircraft when a flight display dies is not very accurate, even though
> NTSB Part 830 requires, somewhat vaguely, pilots to report the
> in-flight failure of electrical systems that require sustained use of
> .backup power to retain flight control or essential instruments.
> Has anybody had, or know of someone who had, a major glass malfunction
> and did it get reported and to whom? The purpose is not to rat out the
> manufacturers but to insure that weak points get fixed before someone
> is hurt.
>
> Bruce Landsberg
> Executive Director, AOPA Air Safety Foundation
>
>
>
>
> *
>
>
> *
> Checked by AVG - http://www.avg.com
>
Message 14
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Subject: | Article from AOPA on Glass EFIS failures |
>>An unanticipated event may be able to take out even a well designed elect
rical bus that has passed multiple peer reviews (Diamond twin star, for exa
mple), <<
Ah... what makes you assume it passed multiple peer reviews ?
By whom? When ?
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Subject: | Re: Charging a low battery |
paul wilson wrote:
>
> I think this has been discussed before, but I vaguely remember. Why
> doesn't my truck blow the 30a fuse when I use it to charge my nearly
> dead trailer batteries (less than 9v)? I have had to do this several
> times and I just connect the truck to the trailer up start the engine
> and rev it up. No ill effects to report and the fuse did not fail.
> The truck has a 110a alternator and 2 size 65 batteries (diesel).
> During this charging I see 13.8v or so on the cigar lighter plug.
> Thanks, Paul
What is the path resistance between from the alternator, to the trailer
battery and back again?
The trailer batter is at 9V and the alternator is putting out 13.8V.
That gives you 4.8V to drive current with. 0.16 Ohms will limit 4.8V to
30A. In that circuit, you've got at least 30ft of wire (of unknown
gauge), two pin connectors (probably half corroded if they look like the
ones on the back of my truck), and two battery connections of unknown
condition. Half an ohm would be no problem to mix in there somewhere.
--
http://www.ronpaultimeline.com
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