backup for vacuum pump/attitude indicator failure

I've been struggling with the same issue. I have a 396 but not a 430. I
also want more utility out of my airplane.

I finally said screw it..... I ordered the electric backup attitude
indicator from Sporty's. $1,871.45 with the AOPA discount. All of the
other options are not really usable. This way I have two indicators inches
apart that require no switching, batteries, cables, etc....


"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

I have the precise flight setup. I've never had to use it but, my sense
is that the vacuum failure light may be the most valusable component.

Blanche wrote:
Concerning the scan to recognize a failure...In addition to the
backup, Precise Flight also offers a lamp that is triggered by
vacuum pump failure. An immediate warning rather than waiting to
discover it. True, it doesn't offer any redundancy, but minimizes
the time to identify a problem.

Of course I recognized my AI failure immediately -- I was turning
right and the AI turned left....

Maule Driver wrote:
I have the precise flight setup. I've never had to use it but, my sense
is that the vacuum failure light may be the most valusable component.

The light is good if you don't have one.

----
Directed to the OP (I'm sure MD knows this):
If you go with the Precise Flight, be sure you check the shuttle valve
frequently as described for preflight in the POH Supplement. The shuttle
valve can stick and then when you need it, it doesn't work. Just the act
of checking it causes the valve to operate and probably helps keep it
from sticking.

Also be sure you understand the operating limitations - altitudes and
power settings where it works and doesn't.

On Sun, 19 Nov 2006 16:45:31 -0600, Jim Macklin wrote:

yes

See the current "Tech Topics" article in CPA Magazine. It's not quite as
clear-cut an answer as this.

- Andrew

On Mon, 20 Nov 2006 13:43:01 -0500, Dave Butler wrote:

Also be sure you understand the operating limitations - altitudes and
power settings where it works and doesn't.

I have to say: I don't like this system. One time when you want happy
gyros is when low and busy...like on a missed approach. But the
full-throttle of the missed means that the gyros are spinning down.

Plus, of course, there's the fact that it does nothing for an AI or
plumbing failure.

- Andrew

On Mon, 20 Nov 2006 10:49:16 -0600, dlevy wrote:

I finally said screw it..... I ordered the electric backup attitude
indicator from Sporty's. $1,871.45 with the AOPA discount. All of the
other options are not really usable. This way I have two indicators
inches apart that require no switching, batteries, cables, etc....

I'm leaning towards one of the portable GPS units that come with the
ability to use an electronic "gyro" (no parts actually spinning). They
tend to be more expensive than the Sporty's AI, but not by that much. And
they tend to have some fun additional features (ie. weather, HITS, and
even traffic).

But what I most like about this solution is that it's not just an
AI/vacuum backup. It is also backing up electrical power and GPS.

- Andrew

I have a lowrance 100 and a palm with hanger18 software for backup attitude.
It's a cable nightmare and the palm has to have fresh batteries. It's not
real reliable either.

Imho, nothing beats the Sporty's option.

"Andrew Gideon" wrote in message
news
On Mon, 20 Nov 2006 10:49:16 -0600, dlevy wrote:

I finally said screw it..... I ordered the electric backup attitude
indicator from Sporty's. $1,871.45 with the AOPA discount. All of the
other options are not really usable. This way I have two indicators
inches apart that require no switching, batteries, cables, etc....

I'm leaning towards one of the portable GPS units that come with the
ability to use an electronic "gyro" (no parts actually spinning). They
tend to be more expensive than the Sporty's AI, but not by that much. And
they tend to have some fun additional features (ie. weather, HITS, and
even traffic).

But what I most like about this solution is that it's not just an
AI/vacuum backup. It is also backing up electrical power and GPS.

- Andrew

Blanche wrote:
Concerning the scan to recognize a failure...In addition to the
backup, Precise Flight also offers a lamp that is triggered by
vacuum pump failure. An immediate warning rather than waiting to
discover it. True, it doesn't offer any redundancy, but minimizes
the time to identify a problem.

Of course I recognized my AI failure immediately -- I was turning
right and the AI turned left....

The concern about noticing a failed pump quickly is one of the reasons
I got the voice annunciator system. That and the gear warning horn is
hard to distinguish from the stall horn. I now have something like 8
channels hooked up and I like it.

-Robert