Avionics failure yesterday...

Jose wrote:
That's correct. However, there was nothing critical to repair. The
alternator tripped, that's all. The engine's still turning, the
weather's severe clear (albeit night), plenty of gas; I saw nothing of
any urgency. Even if the battery totally died, I could circle Danbury
and get a light gun.

With a dead battery, you'd not only have no radio, but also no lights and
no transponder. What makes you think the tower would even have a clue you
were there?

With one of the pax not feeling well, I'd be thinking getting on the
ground at the first reasonable opportunity.

... and then what?

Get the airplane fixed and/or rent a car to get your pax home.

Roy Smith wrote:
Jose wrote:
That's correct. However, there was nothing critical to repair. The
alternator tripped, that's all. The engine's still turning, the
weather's severe clear (albeit night), plenty of gas; I saw nothing of
any urgency. Even if the battery totally died, I could circle Danbury
and get a light gun.

With a dead battery, you'd not only have no radio, but also no lights and
no transponder.

I was wondering if I was the only one who noticed that. I've only had
one complete avionics failure, and it of course affected the transponder
as well. We put it on 7600 in case everything came back on, but
thankfully the radios stayed on long enough that tower knew our
intentions...and long enough that we got yelled at for not having a
transponder on... :-)

With a dead battery, you'd not only have no radio, but also no lights and
no transponder. What makes you think the tower would even have a clue you
were there?

They were expecting me. I had already told ATC my intentions. I'd be a
primary target until I dropped below radar. I've landed without lights
before, it's no big deal. Had I not been able to get landing lights,
then I might have needed to divert to an airport that had them. But if
the failure were one that would drain the battery before I got to
Danbury (it was about twenty minutes away tops), it would likely have
drained no matter where I picked. I think the nearest airport was New
Haven or Bridgeport; DXR isn't much further.

I was wondering if I was the only one who noticed that.

I noticed that, at the time. In fact, since I turned off the lights and
the transponder, I was already in that state. I just had to be extra
vigilant.

... and then what?
Get the airplane fixed and/or rent a car to get your pax home.

I suppose. But yanno, everything is risk for benefit. The additional
risk of continuing with no alternator at night for about fifteen minutes
was one I judeged acceptable for the benefit of not having to deal with
hours of hassle.

It's not like a crash was imminent, or even likely.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

Had I not been able to get landing lights

I meant runway lights.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

That's what windsocks are for.

I don't believe a fly-over was a good choice in the situation, Ron.

NORDO is not an emergency. Burning stuff IS however.

Right. Question was, *was* there something burning, or smoldering, or
no? As more time went by with no further signs, the "no" became
reinforced.

My experience with electronics (limited) made me think it was a cap or
resistor that went, in which case no more circuit and no real fire
danger.

In flight fires are nothing to sneeze at. The fire potential is a
much bigger issue than the nuisance of having no radios VFR. ATC
can fend for themselves.

In retrospect, I agree with you, in that I should have just turned the
master off and left it there.

And make sure it has alkalines or some other non-self-discharging
batteries in it. Nothing like finding the nicads in your handheld are
dead when you need it in such a situation.

Yeah, I recharge them twice monthly.

There's no real point to it in this case.

Glad you agree with that.

Glad it all worked out for you.

Thanks. In reality, it was not a big deal. It's what it could have
been had there actually been a fire.

I
Peter R. wrote:
wrote:

Would welcome any comments on the experience.

A couple of thoughts:

Perhaps call the ATC facility that was last handling your aircraft once on
the ground and explain to them what happened?

or, use your cell while in the air to call FSS to relay a msg to ATC?

I tried to call the TRACON but could not find the number. I know
they're somewhere! So I called the tower, only number I could get, and
left a short message with a plea to relay it. No call back.


--
Peter

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!

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!

Well... maybe. I agree you did the right thing, but in a different
situation, where you needed to communicate, there might have still been
a way.

If you key the mike, does the TX light up? You could go to 121.5 and
use morse code. Clumsy, but possible in a true emergency, so long as
you don't get distracted by it.

It might be that they can hear you but you can't hear them. Ask a tower
for a light gun signal - see if you get it. That will let you know
they can hear you (or not). You could at least say intentions if you
were in more dire straits.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

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

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.

I have also heard of aircraft that have a "backup" set of jacks that are
directly connected to the #1 COM, bypassing the audio panel entirely.

It might be worth a little time to fully familiarize yourself with the
various audio panels you might encounter....



wrote in message
oups.com...
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!