Avionics failure yesterday...

On Tue, 26 Sep 2006 15:31:50 -0700, "Jay Beckman"
wrote:


"Peter Clark" wrote in message
.. .
On 25 Sep 2006 19:43:30 -0700, wrote:

At first I read this as the master, but I think you meant the avionics
master. Did any radio lights come on? Did the transponder do its
transponder blikey thing?

It was the avionics master, yes. Everything but the audio panel came
back on - the radio were just fine, but with a dead audio panel there's
no way to use them!

The 2000 SPs have dual-bus avionics masters. Just curious, did you
try just one side of the switch?

???

THE Master is a two-part red switch (ALT/BAT) but AFAIK, the "Avionics
Master" is a one piece white switch.
Of course, each component has it's own on-off interface.

The new Skyhawks/Skylanes etc (I believe it's back to the restart of
the line) have 2 busses and a split avionics master as well.

"Peter Clark" wrote in message
...
On Tue, 26 Sep 2006 15:31:50 -0700, "Jay Beckman"
wrote:


"Peter Clark" wrote in message
. ..
On 25 Sep 2006 19:43:30 -0700, wrote:

At first I read this as the master, but I think you meant the avionics
master. Did any radio lights come on? Did the transponder do its
transponder blikey thing?

It was the avionics master, yes. Everything but the audio panel came
back on - the radio were just fine, but with a dead audio panel there's
no way to use them!

The 2000 SPs have dual-bus avionics masters. Just curious, did you
try just one side of the switch?

???

THE Master is a two-part red switch (ALT/BAT) but AFAIK, the "Avionics
Master" is a one piece white switch.
Of course, each component has it's own on-off interface.

The new Skyhawks/Skylanes etc (I believe it's back to the restart of
the line) have 2 busses and a split avionics master as well.

My apologies...

You are entirely correct.

Jay B

wrote in message
ups.com...
Well, I haven't posted here in quite awhile. I'm an IFR-rated PP with
about 400 hours currently. Lately flying about 8 hours a month on
average.

Had an interesting experience yesterday: a "hard" avionics failure
complete with something popping/blowing/burning. Flying a very nice,
new (2000) rented 172SP, there was a pop, the audio panel went dead,
and then an acrid odor in the cabin.

After the couple seconds of stark surprise I flipped the avionics
master off. When it appeared there was no real smoke and the smell
disappated I tried cycling the master. Nothing bad, but no audio panel
(completely dead) and thus no radios.

I had just traversed a class C area and was still on with approach when
losing the stack. I also happened to be damned near over an
uncontrolled field (a generally busy one though approach had called out
no traffic and none was visible in the pattern 1000' or so below me).
I decided that I should really land there and pulled the throttle out.
#1, home field is controlled and I had no radios. #2, since something
had definitely 'burned' under that panel, I wanted the airplane on the
ground.

Of course I couldn't get the WX there with no radios. Airport has a
4/22 and 14/32. Local winds were generally N-NW. After a slow 180 to
lose alt I was more or less lined up with 4 and decided that would
work. However, on short final I noted that I was crabbing a good 30d
and was high as well, though I could have lost the remaining alt with a
slip and full flaps easily enough. However, since though I was now
NORDO it was not an emergency situation, I decided to do a climing 270
turn into 32, which I did, and was on the ground pretty quickly, all
the while looking around everywhere for traffic (none).

Taxied to the FBO and grabbed a car back to home airport (45 minute
drive - was on local sightseeing flight with a coworker and
girlfriend).

Overall, in retrospect, I was largely happy with my performance as I
didn't panic or anything of that sort (inexcusable) and got the
aircraft on the ground pretty quickly. However, I should have done at
least one thing differently: I should have either left the avionics
master off or, if leaving it on as I did once determining there was no
danger, I should have squawked 7600. I never changed my squawk. I
elected to leave the panel on mainly to give ATC the benefit of my
return, being right on the border of their airspace, and didn't change
the squawk because I didn't really think of it. Priority was landing
and getting out of the airplane.

Oh, I'd also verified the extinguisher on board and had it at the
ready.

Haven't heard back from the owner yet (local FBO) but I'd imagine a
resistor or cap in the audio panel itself went. No breaker had popped
(the audio panel doesn't have its own breaker).

Lessons learned:

1) ALWAYS have handheld with me. I own one - I'd left it in my own
152, which is what I usually fly. Nothing but laziness in not taking
it with me. (What could go wrong on a short, local flight, after
all?!)

2) Take a bit of time to think about a squawk in any lost-comm
situation. Really, it would have taken 5s to change the squawk and I
had plenty of time.

Would welcome any comments on the experience.


Try, Total G1000 failure (Rebooting PFD every 15 to 20 min) 200 miles over
the Atlantic Ocean In IMC at Night that will keep you on your toes!!!! NO
VHF coverage and limited HF coverage also!!! I Will tell the full story
another day I have been home for a short time and need to rest up was a long
2 weeks! Oh more photo on the way Jay!

Ron Natalie writes:

Even plain old Alkalines will work. The problem is NiCads and NiMH
suffer from self discharge which is excacerbated by heat (i.e.,
leaving the radio to bake in closed up airplane).

Alkaline batteries slowly self-discharge, too. For the slight
increment in cost of lithium, it seems like a good investment for
things that really might have to work after sitting unused for long
periods. Also, lithium batteries don't leak, ever (at least not in my
experience). The lighter weight always helps, too.

Some lithium batteries can overheat or explode if shorted out, which
is why they are not allowed on aircraft. However, batteries like the
standard lithium AA cells have integrated overcurrent protection that
prevents this from happening. If you're using something that requires
special, fancy cells, it's important to see if they have this type of
protection before bringing them on board. I don't know what kind of
batteries handhelds require.

--
Transpose mxsmanic and gmail to reach me by e-mail.

With most modern audio panels, when they fail, you still have a connection
to the mic and headset jacks on the #1 COM. You can test this by simply
turning the audio panel "off" and seeing if the #1 COM works.

There's an emergency switch. It turns out I had forgotten about it
and, yes, I should've been a bit more familiar with all the avionics -
who ever thinks an audio panel has any real complexity?? It doesn't,
but there is a thing or two to know.

If I'd have been in the air for any *significant* time, though, I'm
pretty confident I'd have figured it out.

Switching it "off" does *not* result in COM1 pass-thru. It was off -
dead - the whole time.

"Switching it "off" does *not* result in COM1 pass-thru. It was off -
dead - the whole time."

In most installations, you CAN test the emergency override by turning the
audio panel "off". Intercoms frequently also provide the same capability.

Note that I said "test".

If you have smoke coming out of the audio panel you may well be suffering
component and/or wire damage. Obviously this could affect even "emergency"
operations...





wrote in message
oups.com...
With most modern audio panels, when they fail, you still have a
connection
to the mic and headset jacks on the #1 COM. You can test this by simply
turning the audio panel "off" and seeing if the #1 COM works.

There's an emergency switch. It turns out I had forgotten about it
and, yes, I should've been a bit more familiar with all the avionics -
who ever thinks an audio panel has any real complexity?? It doesn't,
but there is a thing or two to know.

If I'd have been in the air for any *significant* time, though, I'm
pretty confident I'd have figured it out.

Switching it "off" does *not* result in COM1 pass-thru. It was off -
dead - the whole time.

Nothing bad, but no audio panel
(completely dead) and thus no radios.


That's unusual. Normally, the COM1 should work failsafe through it,
unless cables break. You should look into that - might be the wiring.

Also, as you say yourself, that's exactly the situation 7600 is meant
for.

--
Thomas Borchert (EDDH)

Ron,

I wouldn't bother sqawking IFR.


Huh? 7600 has NOTHING to do with IFR. It's the lost comm squawk. It
would have helped ATC tremendously to know what was going on with this
guy they were talking to. There was a very real point in setting 7600.
How could it not be?

--
Thomas Borchert (EDDH)

who ever thinks an audio panel has any real complexity??

Uhm, I do. Did so from day one.
It doesn't,

Switching it "off" does *not* result in COM1 pass-thru. It was off -
dead - the whole time.

Then it is not correctly wired.

--
Thomas Borchert (EDDH)

Thomas Borchert wrote:
Ron,

I wouldn't bother sqawking IFR.


Huh? 7600 has NOTHING to do with IFR. It's the lost comm squawk. It
would have helped ATC tremendously to know what was going on with this
guy they were talking to. There was a very real point in setting 7600.
How could it not be?


He was VFR outside of any airspace that required communications and
going to land. Just how would 7600 done a whole lot for this situation?