First Time in IMC and vacuum problem

I too had my first experience in IMC yesterday. I got my ticket last
summer too and have kept current but haven't had a chance to go solo. I
was going to go from Indianapolis Executive (TYQ) to Capitol City in
Lansing Michigan (LAN). The weather was 1000 OVR until 50 miles north of
TYQ and then it was clear all the way to LAN. THis was going to be a
quick trip because the weather in Indiana was forecast to get worse as
the day wore on.

I was a little bit apprehensive because I have a respect to IMC but I
thought it would be good practice too. I got set up, picked up my
clearance and was off. Just as forecast I entered the clag at 1000 feet.
Right away I spotted something wrong with the attitude indicator. It was
looking like I was in a steep climbing turn. Oh **** I thought great
time for the AI to go out. I had a weird feeling of ending up as an
Aftermath column. I must say that I was pretty scared but strange
enough not panicked. I reduced power, used the Turn Coordinator to level
the wings, used the Airspeed Indicator to level off altitude. I called
ATC and told them that I was having a problem with the AI and needed
their assistance. They asked if I wanted vectors back to TQY to shoot
the ILS 36 there. I said yes. I started back to the field and the AI
started to act like I expected it should. After a few minutes I was
still in the clag but all instruments were working correctly. I thought
about just continuing on back to Lansing but I quickly talked myself out
of it.

Really after I "calmed" down and the AI started acting correctly I
didn't have any problems navigating in the clouds. I shot the ILS 36 and
broke out 1000 feet above the runway, canceled my IFR flight plan and
made an uneventful landing. ATC wanted to know if I wanted to refill my
flight plan and I said no thanks. I was glad to be on the ground. I was
thinking about what just transpired and decided to talk it over with my
CFI.

We determined that what probably happened was that the extended period
of idling on the ground caused the AI gyro to spool down some. It took
several minutes at cruise power for it to come back up to speed and
after that it indicated correctly.

Here is what I'll do different next time:

1. Make sure that I have had the vacuum indicator "in the green" for
several minutes before departing to ensure that the gyros are spooled up.

2. Have the approach for returning to the airport loaded or in standby
just in case you need to return quickly. I did not do this and it added
needless stress loading everything.

It is true what they say:
"It is better to be on the ground wishing you were in the air, then
being in the air wishing you were on the ground"

Jon Kraus
PP-ASEL-IA
Student Mooney Owner

In a previous article, Jon Kraus said:
1. Make sure that I have had the vacuum indicator "in the green" for
several minutes before departing to ensure that the gyros are spooled up.

2. Have the approach for returning to the airport loaded or in standby
just in case you need to return quickly. I did not do this and it added
needless stress loading everything.

It couldn't hurt to have a mechanic look at your vacuum system.


--
Paul Tomblin http://xcski.com/blogs/pt/
"The means of defense against foreign danger historically have become the
instruments of tyranny at home." - James Madison

I didn't mention that in my post but first thing tomorrow I am calling
the shop and have them check everything out. Thanks!!

Jon Kraus
PP-ASEL-IA
Student Mooney Owner

Paul Tomblin wrote:
In a previous article, Jon Kraus said:

1. Make sure that I have had the vacuum indicator "in the green" for
several minutes before departing to ensure that the gyros are spooled up.

2. Have the approach for returning to the airport loaded or in standby
just in case you need to return quickly. I did not do this and it added
needless stress loading everything.


It couldn't hurt to have a mechanic look at your vacuum system.

My guess is you have a failing vacuum pump. It might have been acting up
then corrected itself during flight once you had full RPM. Even if the
vacuum is below green during idle, it should not take more than a few
seconds to bring the gryos to full speed at takeoff power. I would
definitely have the vacuum system checked out.





(Paul Tomblin) wrote in news:cr8uan$4n2$1
@allhats.xcski.com:

In a previous article, Jon Kraus said:
1. Make sure that I have had the vacuum indicator "in the green" for
several minutes before departing to ensure that the gyros are spooled up.

2. Have the approach for returning to the airport loaded or in standby
just in case you need to return quickly. I did not do this and it added
needless stress loading everything.

It couldn't hurt to have a mechanic look at your vacuum system.

Dry vacuum pumps normally fail catastrophically by shattering their
graphite vanes. Personally, I've never detected warning signs other =
than
gradually accumulating carbon dust around the pump outlets.
When I see that, I schedule pump replacement without waiting for =
failure.

Jon's doing right by getting the whole vacuum system checked.
He could have a clogged filter, a small leak, or even a bad gyro =
bearing.

"Andrew Sarangan" wrote in message =
1...
=20
My guess is you have a failing vacuum pump. It might have been acting =
up=20
then corrected itself during flight once you had full RPM. Even if =
the=20
vacuum is below green during idle, it should not take more than a few=20
seconds to bring the gryos to full speed at takeoff power. I would=20
definitely have the vacuum system checked out.

(Paul Tomblin) wrote in news:cr8uan$4n2$1
@allhats.xcski.com:
=20
In a previous article, Jon Kraus said:
1. Make sure that I have had the vacuum indicator "in the green" for =

several minutes before departing to ensure that the gyros are spooled =
up.

2. Have the approach for returning to the airport loaded or in =
standby=20
just in case you need to return quickly. I did not do this and it =
added=20
needless stress loading everything.
=20
It couldn't hurt to have a mechanic look at your vacuum system.
=20

Well, I have seen signs of dry pumps show signs of failure. True, the
ultimate failure is catastrophic, but every time I found a low vacuum
reading they found some problem with the pump. After replacement, the
vacuum was back up to where it should be.



"John R. Copeland" wrote in
:

Dry vacuum pumps normally fail catastrophically by shattering their
graphite vanes. Personally, I've never detected warning signs other
than gradually accumulating carbon dust around the pump outlets.
When I see that, I schedule pump replacement without waiting for
failure.

Jon's doing right by getting the whole vacuum system checked.
He could have a clogged filter, a small leak, or even a bad gyro
bearing.

"Andrew Sarangan" wrote in message
1...

My guess is you have a failing vacuum pump. It might have been acting
up
then corrected itself during flight once you had full RPM. Even if
the
vacuum is below green during idle, it should not take more than a few
seconds to bring the gryos to full speed at takeoff power. I would
definitely have the vacuum system checked out.

(Paul Tomblin) wrote in news:cr8uan$4n2$1
@allhats.xcski.com:

In a previous article, Jon Kraus said:
1. Make sure that I have had the vacuum indicator "in the green"
for

several minutes before departing to ensure that the gyros are
spooled
up.

2. Have the approach for returning to the airport loaded or in
standby
just in case you need to return quickly. I did not do this and it
added
needless stress loading everything.

It couldn't hurt to have a mechanic look at your vacuum system.

In a previous article, "John R. Copeland" said:
Dry vacuum pumps normally fail catastrophically by shattering their
graphite vanes. Personally, I've never detected warning signs other than
gradually accumulating carbon dust around the pump outlets.
When I see that, I schedule pump replacement without waiting for failure.

Jon's doing right by getting the whole vacuum system checked.
He could have a clogged filter, a small leak, or even a bad gyro bearing.

We had an AI once that was very slow to erect. First the mechanic
increased the suction to try and spin the gyros faster, but when that
didn't help we ended up replacing the AI.


--
Paul Tomblin http://xcski.com/blogs/pt/
I treat shops as military objectives to be penetrated and stripped of needed
resources in as little time as possible. She has adventures in them.
-- Joe Thompson

Mine did that before it failed.

Jon Kraus wrote:
We determined that what probably happened was that the extended period
of idling on the ground caused the AI gyro to spool down some. It took
several minutes at cruise power for it to come back up to speed and
after that it indicated correctly.

You should be getting full vacuum at normal ground idle speeds (1000 RPM
or so). If your gyros are not spinning up in the time it takes you to
taxi to the runway and do a normal runnup, something is wrong with the
vacuum system or the gyros.

In any case, congrats on a job well done.

"Jon Kraus" wrote:
Right away I spotted something wrong with the attitude indicator. It
was
looking like I was in a steep climbing turn. Oh **** I thought great
time for the AI to go out. I had a weird feeling of ending up as an
Aftermath column.

Holy sh**!

[snip good job of getting back on the ground]

Here is what I'll do different next time:

1. Make sure that I have had the vacuum indicator "in the green" for
several minutes before departing to ensure that the gyros are spooled
up.

2. Have the approach for returning to the airport loaded or in
standby just in case you need to return quickly. I did not do this and
it added needless stress loading everything.

My first thought if I have trouble in IMC is to get to VMC if I can do
it quickly. Did you have any idea of where the tops were? If you could
have made a short, straight ahead climb above the clouds, your
destination was in the clear; you could have avoided a bunch of IMC
maneuvering with a flaky AI.
--
Dan
C172RG at BFM