backup for vacuum pump/attitude indicator failure

Hint, unless a homebuilt, all parts must be approved parts.

Is this really true? I cannot mount an unapproved CD player someplace
so that it won't flop around in flight?

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.

My Husky had a really nice minimal IFR panel. A KX155 Nav/Com, a King
KLN90B (with its own seperate CDI), and a Century I autopilot that was
all electric and worked off the turn and bank. Loose the electric and
you still have the DG and AI. Loose the vacuum and you still have the
autopilot and the turn coordinator AND the GPS (which can work as a DG,
sort of). Top that all off with a handheld radio (with its own antenna)
and a handheld GPS (with it's own permanently mounted outside antennae)
and its pretty damn backed up.

Just a little story about flying with failed instruments.

I was flying with an instrument student, and had been telling him the
importance of the gyroscopic instruments to maintaining control of the
airplane in the clouds. So I covered up one gyro, he kept flying along
fine. He was under the hood, we were flying mostly straight and level,
maybe some simple level turns, don't remember all the details now. Then I
covered up the second gyro. He kept flying along fine. So I covered the
third gyro, expecting him to soon wind up in a spiral dive. He kept flying
along fine. So finally I asked him how he was doing it. I had forgotten
about the GPS. He was watching the TRK number on the GPS, and that was
giving him essentially the same data as the DG, although with a slower
update rate. Along with the pressure instruments, he was doing just fine.




"Kelly" wrote in message
ups.com...
I would be interested in getting opinions about backup systems for a
vacuum pump failure and/or AI failure. I have a 172P with a single
vacuum pump system, standard instruments otherwise, and a Garmin 430.
I am most concerned about having a good backup if I lose a vacuum pump
or AI in IMC. I have been thinking about either a Garmin 396/496 or
the electric AI available from Sporty's. Looks like I could get a 396
or installed electric AI for about the same price ($2200 or so). While
I haven't seen the panel page/"6-pack" page on the 396 or 496, I have
read (in Aviation Consumer) that it's good enough to keep control of
the airplane in an emergency situation. Obviously, the 396/496 has a
number of other neat features such as inflight weather, terrain info,
etc. Any suggestions on which way to go with this.

BTW, I had also considered the Precise Flight backup vacuum system for
a while, and it certainly is cheaper (around $700 installed). However,
I was concerned by the fact that it would do nothing for you in the
event of failure of the AI vs. the primary vacuum pump.

Thanks.
Kelly

yes


"Jose" wrote in message
m...
| Hint, unless a homebuilt, all parts must be approved
parts.
|
| Is this really true? I cannot mount an unapproved CD
player someplace
| so that it won't flop around in flight?
|
| 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.

Thanks for all the helpful comments so far. In thinking about what you
all have said, with my current setup (and yes I am an owner), I would
realistically have a DG with either a vacuum pump failure or AI
failure. In the case of a vacuum pump failure, I could still get
current ground track from the 430. And, obviously with the AI failure
alone, I would still have the DG.

While I don't do a lot of flying in actual IMC, I do enough that I'm
willling to spend some extra money to hopefully prevent a major problem
in the event of vacuum pump failure. I don't know about the rest of
you, but if I encounter a situation where I end up flying partial
panel, I plan to get in VMC ASAP, or if I can't do that, land.

I haven't yet flown with any of the Garmin handhelds, but my guess (and
I could certainly be off on this) is that would be harder to use the
panel page on the handheld as a backup versus having a backup electric
AI and thus the traditional instrument panel gauges and layout that I
trained on. The electric AI from Sporty's also has the ball
inclinometer built into it and can replace the turn coordinator.

So, if anyone else wants to weigh in on best bang for the buck backup,
here again are the options in contention:

1. Engine driven backup vacuum (such as Precise Flight)
2. Electric AI
3. Garmin 396/496
4. $2 failed-instrument covers (I need these anyway, but I had to
throw this in as an option).

Thanks again.

Kelly

The 396/496 gives you XM-WX capability, which you can also add to your '430.
If you already have the weather capability in your '430, I'd opt for a
lower cost Garmin, like a 196, to provide backup GPS and, most critically, a
backup for the DG (by placing the 196 in the HSI mode). Either way, I'd
also add an electric backup AI

-Elliott Drucker

Is this really true? I cannot mount an unapproved CD
player someplace
so that it won't flop around in flight?
yes

Actually, I spoke to our FSDO not too lona ago with this very question,
and the answer came back that it is legal to do so. The =installation=
needs to be approved (the installer can self-approve) but the device
being installed need not be an approved device, so long as it is not
powered directly by the aircraft system (cigarette lighter power is ok).

They are concerned that the installation not interfere with flight
controls and such. They are concerned that a non-approved device not
take the place of an approved instrument, but according to my FSDO, once
I explaned all we wanted to do (install an electric backup AI), they
were ok with it.

YMMV

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.

4. $2 failed-instrument covers (I need these anyway, but I had to
throw this in as an option).

5: MSFS and practice.

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.

Kelly wrote:

I would be interested in getting opinions about backup systems for a
vacuum pump failure and/or AI failure.
..stuff snipped
Looks like I could get a 396
or installed electric AI for about the same price ($2200 or so). While
I haven't seen the panel page/"6-pack" page on the 396 or 496, I have
read (in Aviation Consumer) that it's good enough to keep control of
the airplane in an emergency situation. Obviously, the 396/496 has a
number of other neat features such as inflight weather, terrain info,
etc.

Funny you should ask. I covered up my AI and DG and tried flying via the
panel page on my 396. Downright freaky. I figured the lag would not be
too bad but it really does present a challenge. I suppose with practice
it might do. But in bumpy IMC I might be chasing the TC and altimeter
indications all over the place. The 496 has a faster refresh that may
make this less of an issue.

On the other hand, the lag might keep me from overworking the controls
as I often do in IMC on a bumpy day. You won't correct for every little
deviation because the unit won't update that fast.

I like the idea of that little box that had solid state gyros in it and
you would velcro to the floor and hook up to a PDA. Instant electric
gyros without the gyro wear and tear. If only you could USB the signal
into the 396...

Good Luck,
Mike

Is this really true? I cannot mount an unapproved CD player someplace
so that it won't flop around in flight?

yes

Not true in the slightest. You want to velcro your CD player to the top
of the glareshield or maybe to the floor have at it. I have my
satellite radio attached to the far left side of the panel with that two
sided 3M sticky tape they give you with the radio. That stuff is better
than screws because when I want to remove it you'll never know it was
there and if you've worked with that tape before you know how solid it
is. I run the power, antenna and audio out cables under the glareshield
and then out to where they need to go.