Avionics failure yesterday...

"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.

Jay B

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.

wrote:
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.

Sounds like you did everything right. Don't beat yourself up nit-picking
some minor detail that you might have done differently.

If you had no radios, what makes you think the xponder was working? And,
more to the point, even if it was, what do you think would have happened
any differently if you squawked 7600?

2) Take a bit of time to think about a squawk in any lost-comm
situation.

That is certainly true, but more generally, once you've determined that
there's no immediate danger in any abnormal situation, take the time to
think. As long as the engine's still turning, the wings are still
attached, and you're not on fire, you've got time to take stock of what's
happening and figure out a plan.

A headset will still work, even though the speakers won't.
You'll have to set volume controls.


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.
|

wrote:
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.

If it turns out to be the panel that failed, and depending on the
warranty policies of the panel manufacturer, it might be interesting
if the aircraft owner can get a local tech to open up the panel.
This is within the date range of a big batch of bad capacitors; they
are most famous for failing on PC motherboards, but they have turned
up in lots of places: http://en.wikipedia.org/wiki/Capacitor_plague

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.

Disclaimer: This is based on very limited experience with audio panels
(real panels, but installed in simulators) a few years back. I thought
some panels had a default "bypass" mode. In other words, under certain
conditions, it connects the pilot's earphones/mic/PTT to COM 1 and
that's it. You don't get an intercom or the Dolby 5.1 surround from
the DVD player or anything else, but you can use one of your radios.

The way to get into this mode probably varies. Simply shutting off the
audio panel might do it. If the "bypass" is implemented with an
electromechanical relay, it should even still work under many of the
failure conditions of the audio panel - if the power to the relay coil
drops out, the contacts will make the default connection. On an older
panel with the "only one at a time" mechanical switches on the front,
pushing one of the switches in halfway and then releasing so that none
of the switches are pressed might do it. The manual (or careful
experimentation) may help.

If audio panels _don't_ do this, or if the old ones did but the new
ones don't, I wonder if it would be useful to have a headset jack that
connects directly to COM 1 and doesn't go through the audio panel. That
way, if you lose the panel but not the radio, you can plug your headset
into the "direct" jack and still use COM 1. I realize you don't get to
add your own jacks to a rental plane - this is more of a general "would
this be useful" question.

1) ALWAYS have handheld with me.

A couple of people have mentioned having good batteries in it as well.
If you want to be able to just pick up the handheld and talk, this may
not work very well. Also, none of this stuff is as critical as a backup
radio in an airplane. Having said that, I have a couple of portable
devices that I run NiMH AA batteries in. What I do is to have a couple
of sets of NiMH and a fresh set of alkalines. If I go through both sets
of NiMH, I can then put in the alkalines while I decide what to do next.
The alkalines don't mind sitting around for a few months doing nothing,
and if I haven't used them after several months, I'll use them somewhere
else and get a fresh spare set of alkalines for the portables.

Matt Roberds

wrote:

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.


Be sure you have a head set adapter. Handhelds are very hard to use with
all the noise. I have one.
--

Regards, Ross
C-172F 180HP
KSWI

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!

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)