Avionics failure yesterday...

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:

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?

--
Peter

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

wrote:


Of course I couldn't get the WX there with no radios. Airport has a
4/22 and 14/32.

That's what windsocks are for.

However, since though I was now
NORDO it was not an emergency situation,

NORDO is not an emergency. Burning stuff IS however.


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.

Without being IFR or someplace like a class B where communications with
a radar controller is required, I wouldn't bother sqawking IFR. If I
thought things might still be burning I would have left the avionics (or
general) master off.

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.

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?!)

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.


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.

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

Glad it all worked out for you.

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.

wrote:


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


I had a similar thing once. I had just pulled my plane out of the shop
where they had worked on the voltage regulator. I don't know if it was
just my imagination or what but I was sure as I was climbing out I
smelled electrical smoke and thought I might have detected some
visually. I keyed the mike and told the tower I was coming back and
shutting off the master now. I did, and as I am on short final
I notice the entire Air National Guard crash and rescue brigade
racing to the approach end of the runway. Oh well, better safe
than sorry, I just hope they don't drown me in foam before I can
get out of the aircraft.


I mention the batteries because I once was a passenger in a IFR
(but VMC) NORDO plane and the pilot's hand held batteries were
also moribund. I did manage to get clearance to land at Dulles
with only the receiver working.

Ron Natalie writes:

I mention the batteries because I once was a passenger in a IFR
(but VMC) NORDO plane and the pilot's hand held batteries were
also moribund. I did manage to get clearance to land at Dulles
with only the receiver working.

Lithium batteries will hold their charge for a decade at least. They
are also very light, and they provide high current on demand. I use
them exclusively for everything when I have the option.

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

Mxsmanic wrote:
Ron Natalie writes:

I mention the batteries because I once was a passenger in a IFR
(but VMC) NORDO plane and the pilot's hand held batteries were
also moribund. I did manage to get clearance to land at Dulles
with only the receiver working.

Lithium batteries will hold their charge for a decade at least. They
are also very light, and they provide high current on demand. I use
them exclusively for everything when I have the option.


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).

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)

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?