Knocked out a couple of approaches today in IMC conditions. Was cut
short due to a vacuum system problem (note, not the pump).

Ceilings 1500 at KJAN and 1400 on my approach into KMBO.

http://www.youtube.com/watch?v=RCvDb3mCAf8

Just after entering the clouds, saw my attitude indicator show an
extraordinary pitch up. Quick scan of my airspeed and VSI did not
confirm. Since I was IMC decided to continue approach and just work
my partial panel skills. Turning back wasn't an option.

In the full scheme of things, no big deal.

Camera was placed on glare shield for the outside view since I didn't
have a passenger It would have been nice to capture the
instrumentation discrepancies if anything for others to see it happen
under real conditions .but somebody had to man the shop and reaching
for the camera myself was not an option in IMC..

After settling in, just contacted approach and advised them I didn't
have a vacuum system, and would use ground track for my heading
directions. When asked my intentions, I said to continue my ILS
approach into KJAN and then VOR Alpha back to Madison with vectors. I
had in my mind if it was too much work, just would do a full stop at
KJAN.

ATC asked if I needed any assistance and I declined as everything
really was under control.

Used my VSI as my "attitude indicator" figuring if it was level,
airplane was level. If it pointed down, then I figured my nose was
pointed down, and vice versa for pitch up.

While I could have used the TC for bank information, I found it much
easier in my scan just to use the ground track on the Garminm 430. If
it changed, I figured the plane was banking.

Problem I think (still getting this checked into) is the vacuum
regulator as my vacuum gauge was reading 6 out of possible high of
7. Time will tell...

Allen

wrote:
> Knocked out a couple of approaches today in IMC conditions. Was cut
> short due to a vacuum system problem (note, not the pump).
>
> Ceilings 1500 at KJAN and 1400 on my approach into KMBO.
>
> http://www.youtube.com/watch?v=RCvDb3mCAf8
>
> Just after entering the clouds, saw my attitude indicator show an
> extraordinary pitch up. Quick scan of my airspeed and VSI did not
> confirm. Since I was IMC decided to continue approach and just work
> my partial panel skills. Turning back wasn't an option.
>
> In the full scheme of things, no big deal.
>
> Camera was placed on glare shield for the outside view since I didn't
> have a passenger It would have been nice to capture the
> instrumentation discrepancies if anything for others to see it happen
> under real conditions .but somebody had to man the shop and reaching
> for the camera myself was not an option in IMC..
>
> After settling in, just contacted approach and advised them I didn't
> have a vacuum system, and would use ground track for my heading
> directions. When asked my intentions, I said to continue my ILS
> approach into KJAN and then VOR Alpha back to Madison with vectors. I
> had in my mind if it was too much work, just would do a full stop at
> KJAN.
>
> ATC asked if I needed any assistance and I declined as everything
> really was under control.
>
> Used my VSI as my "attitude indicator" figuring if it was level,
> airplane was level. If it pointed down, then I figured my nose was
> pointed down, and vice versa for pitch up.
>
> While I could have used the TC for bank information, I found it much
> easier in my scan just to use the ground track on the Garminm 430. If
> it changed, I figured the plane was banking.
>
> Problem I think (still getting this checked into) is the vacuum
> regulator as my vacuum gauge was reading 6 out of possible high of
> 7. Time will tell...
>
> Allen
Maybe a collapsed hose?

On May 17, 7:08*am, BillJ > wrote:

> Maybe a collapsed hose?

All lines were checked as I experienced this anomaly in VFR
conditions, and it "went away" so we figured like you, a crimped hose
somewhere in the lines became un-crimped when things were poked
around. This happened about 6 flights ago, so I really thought it was
fixed.

wrote:
snip
>
> Used my VSI as my "attitude indicator" figuring if it was level,
> airplane was level. If it pointed down, then I figured my nose was
> pointed down, and vice versa for pitch up.
>
snip
>
> Allen

Why wouldn't you use airspeed or altitude for pitch? It responds faster.
--

Regards, Ross
C-172F 180HP
KSWI

On May 19, 12:51 pm, Ross > wrote:
> wrote:
>
> snip
>
>
>
> > Used my VSI as my "attitude indicator" figuring if it was level,
> > airplane was level. If it pointed down, then I figured my nose was
> > pointed down, and vice versa for pitch up.
>
> snip
>
> > Allen
>
> Why wouldn't you use airspeed or altitude for pitch? It responds faster.
> --

When you are trying to maintain constant altitude (or constant
anything) a differential instrument is better than an absolute
instrument. Although the VSI does have a lag, for small changes it
should not be big factor.

Andrew Sarangan wrote:
> On May 19, 12:51 pm, Ross > wrote:
>> wrote:
>>
>> snip
>>
>>
>>
>>> Used my VSI as my "attitude indicator" figuring if it was level,
>>> airplane was level. If it pointed down, then I figured my nose was
>>> pointed down, and vice versa for pitch up.
>> snip
>>
>>> Allen
>> Why wouldn't you use airspeed or altitude for pitch? It responds faster.
>> --
>
> When you are trying to maintain constant altitude (or constant
> anything) a differential instrument is better than an absolute
> instrument. Although the VSI does have a lag, for small changes it
> should not be big factor.
>
>
>
Why is a differential instrument better? If I wanted to know if I was
level I would look at my altimeter. If I stay at 6000' I am level. If my
airspeed is faster then I am going down or slower then I am going up.
Now that I think about it airspeed might be better, since turbulence
could be bouncing me up and down and I could be chasing that.

--

Regards, Ross
C-172F 180HP
KSWI

On May 19, 11:51*am, Ross > wrote:

> Why wouldn't you use airspeed or altitude for pitch? It responds faster.

Not a matter of response I was looking for, but for me, being the
position of the needle being "level" visually was a cue that I was
level flight. If it pointed down visually, I would visually see the
nose of the plane down, and vice versa for climbs.

I just found it visually easier to interpret the attitude of the plane
using the VSI needle.

Of course, like you said airspeed will give you pitch information as
well as the RPM of the engine to even expand further (good
consideration for icing situations in my head anyway).

As Ross pointed out altimeter would also work, as after all an
assigned altitude is just that, straight and level, if it's going down
your descending and so on but VISUALLY, the VSI gave me a better
picture of my airplane attitude (pitch)

In my simple mind it worked well anyway :-)))

> I just found it visually easier to interpret the attitude of the plane
> using the VSI needle.

If you're doing this in IMC, I hope you have an IVSI.

Hilton

On May 21, 1:58*am, "Hilton" > wrote:

> If you're doing this in IMC, I hope you have an IVSI.

No...... For those that don't know what IVSI is, as I had to look it
up, the IVSI means Instant Vertical Speed Indicater in the above.

The VSI was only a "visual aide" to help verify the trends of my other
gauges. Once I was straight and level, the altimeter was my primary
and VSI was secondary, but a visual to show I was indeed level (thus
me calling my "attitude indicator").

Any change to the sound of my engine would prompt me to look at the
altimeter first and then my VSI, and if the VSI was pointed up, then
it was easier to see I was trending up which meant I was pitched up.
(just gave me a better visual) which of course make me make
appropriate trim settings or control input changes.

Again, my simple ways of dealing with an unusual problem, may not work
for others, but my outcome was of such it worked for me. Just a tool
in my took kit I found fit for my needs.

On 5/16/2008 9:31 PM, wrote the following:
> While I could have used the TC for bank information, I found it much
> easier in my scan just to use the ground track on the Garminm 430. If
> it changed, I figured the plane was banking.
>

I am curious about this. I would have expected TRK to be far too lagged and
imprecise to be useful in keeping the shiny side up.

TRK is nice for when the DG is dead of covered, of course, but I use the TC for
bank. I'll have to try it next time I fly.

On May 21, 2:07*pm, airdale > wrote:
> On 5/16/2008 9:31 PM, wrote the following:
> * > While I could have used the TC for bank information, I found it much
>
> > easier in my scan just to use the ground track on the Garminm 430. *If
> > it changed, I figured the plane was banking.
>
> I am curious about this. *I would have expected TRK to be far too lagged and
> imprecise to be useful in keeping the shiny side up.
>
> TRK is nice for when the DG is dead of covered, of course, but I use the TC for
> bank. *I'll have to try it next time I fly.

TC obviously used in training for secondary instrumentation, but mine
is in the faaaaaaaar lower left corner of my panel, which really
extends the real estate of my scan.

So, figured trk would work best for me since that would be my headings
anyway rather then my wet compass.

My wet compass is a vertical card that hangs from the top of the
windscreen, while great for verifying the DG, not so great when I
don't want to make too much head movement in my scanning process
especially during my approach phase when I do my IFR briefing of the
approach plate.'

Truth be known, I really didn't notice the lag, but if it was there, I
didn't get any complaints from ATC when given my assigned headings for
my approaches.