Mooney Engine Problems in Flight

Paul Smedshammer wrote:
This is a bit long winded but I'm looking for qualified opinions as
to what
might have happed to an almost total loss of power while in cruise
flight in
my Mooney M20F. Here is the story of what happened:

I also own an M20F. Did you have teh ram air on? There are cases of ice
build up when the ram air is on. The owner's manual cautions us to turn
it off in ice conditions.

Have you checked your fuel vents? There have been reports of Mooneys
lossing power after fuel vent blocks. However, changing tanks should
fix that.

The Mooney does have an automatic alternate air system. At annual, the
automatic switching door should be inspected and the spring pressure
should be measured.

-Robert, M20F

In article , "clyde woempner" wrote:
VFR on top, not good if you and the plane are not capable of IFR flight.
Did the forcast call for any broken or scattered conditions along your route
of flight, if so where?? Water in the fuel system can lead to freezing in
the fuel line as you gain altitude. The weather report would give you the
freezing level. This can of course block and/or restict the fuel flow.
But, second guessing the problem is not too smart, I strongly suggest you
have a shop check it out, maybe a fuel pump was sucking air from a loose
fitting, etc. Have it checked out, and watch out for Mt. Diablo. Just
remember, always have options:
Clyde

I agree that VFR on top is not the best idea if you and plane are not capable
of IFR flight. But in this case the Mooney M20F is fully capable of IFR
flight and I'm working on my IFR ticket. Not that my working on it makes any
difference in this case. However, I thought I understood the risk here and
felt that while it was risky to try and make it over this 30 mile socked in
overcast with totally clear skies above, it was worth the risk as I needed to
get home (I know - Get There Itis) and this engine was just over 50 hours SMOH
along with overhauled mags, generator, fuel servo, and prop governor at the
same time. The engine was performing perfectly. Famous last words?

I don't think an IFR ticket would have helped a whole lot in this case. It
would have provided for 1 attempt at an IFR approach with only 45% power
maximum available and 600 foot overcast with 3 miles max visibility in mist
below me.

For those interested, here is photo of what it looked like about 10 seconds
before the event.

http://www.coreutilities.com/mooney/RoughEngine.JPG

Trust me, I learned my lesson and I will not be going VFR on top like this
again without options like enough altitude to glide to a visible landing
site and the IFR ticket in hand. Even then I'm going to think twice about
attempting it. A second engine would have been great to have!
Paul

In article .com, "Robert M. Gary" wrote:

Paul Smedshammer wrote:
This is a bit long winded but I'm looking for qualified opinions as
to what
might have happed to an almost total loss of power while in cruise
flight in
my Mooney M20F. Here is the story of what happened:

I also own an M20F. Did you have teh ram air on? There are cases of ice
build up when the ram air is on. The owner's manual cautions us to turn
it off in ice conditions.

Have you checked your fuel vents? There have been reports of Mooneys
lossing power after fuel vent blocks. However, changing tanks should
fix that.

The Mooney does have an automatic alternate air system. At annual, the
automatic switching door should be inspected and the spring pressure
should be measured.

-Robert, M20F

When this happened I had the power boost off. As one of the trouble shooting
items I opened it and got a slight increase in power like from 30% to 35%.
Hard to judge but it was running extremely rough and opening the power boost
cleaned it up just a little bit. I left it open as it did make things just a
little better. But it was the enriching of the mixture that really made the
difference. Still less than 50% power but it at least ran smoother.

By the way, I LOVE this plane. It is old but it fly's great and I feel the
most comfortable I have ever felt in about 7 different planes types (152, 172,
172RG, 182, Debonair, Warrior, and Arrow). The Mooney just has the
performance I have always been wanting. It is a great plane... as long as the
engine keeps running!

Paul, 1967 M20F

For those interested, here is photo of what it looked like about 10
seconds
before the event.

http://www.coreutilities.com/mooney/RoughEngine.JPG

Trust me, I learned my lesson and I will not be going VFR on top like this
again without options like enough altitude to glide to a visible landing
site and the IFR ticket in hand. Even then I'm going to think twice about
attempting it. A second engine would have been great to have!
Paul

Wow. That photo made my blood run cold. It's beautiful, but knowing that
there's a chance that you have to descend into it is chilling.

I am glad that things turned out OK for you. Thanks for posting.

-Trent
PP-ASEL

Paul Smedshammer wrote:
In article .com,
"Robert M. Gary" wrote:
When this happened I had the power boost off. As one of the trouble
shooting
items I opened it and got a slight increase in power like from 30% to
35%.

Do you know if your shop has done the AD that requires checking the
drain holes in the ribs? Since Mooney stores it's fuel in the wing
(rather than in a real fuel tank), the fuel needs to run through the
ribs. At the bottom of the ribs there are very small holes. When the
tank gets patched its easy to put your B-2 over these holes and create
a small pocket where fuel (and water) can stay trapped for some time.
Some of these holes should be covered (since they are mating points
that can allow fuel leaks) and others are there on purpose (to allow
water and fuel to run through). I wonder if you might have disloged
some water in your flight. Turning on the pump would increase the
amount of fluid running through the system and maybe move the water out
sooner? Just a guess.
-Robert, Mooney CFI and M20F owner (and loving it!!)

Ron Rosenfeld wrote:
I have had problems, over the years, with clogged injector; clogged
fuel
line; and clogged fuel servo. In all of those instances, the EGT for
the
affected cylinder(s) went down when engine roughness was noted.
Except for
the fuel servo when the problem became evident on takeoff and I was
concentrating on landing, rather than looking at EGT's.

I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

-Robert, M20F

Robert M. Gary wrote :
I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

If one plug in a two plugged cylinder quits working, then there is
only one flame front. Instead of the fuel/air charge burning from two
ignition sources, it burns from one. This results in the charge taking
longer to completely burn. Since the charge took longer to burn, the
gasses are still hotter when the exhaust valve opens and the gasses
pass by the EGT probe.

This will happen anytime you go from 2-plug to single plug operation.
When in cruise, switch to one mag or the other. You should see a rise
on all EGTs.

John Galban=====N4BQ (PA28-180)

"Robert M. Gary" wrote:
I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

That's easy: failure of one plug prolongs the burning of the mixture, so
some is still burning as it is ejected out the exhaust past the temp.
probe.
--
Dan
C172RG at BFM

"Robert M. Gary" wrote

I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

-Robert, M20F

Incomplete/slower combustion, gases still burning in the exhaust header- on
the way past the EGT sensor.
--
Jim in NC

Paul:

You didn't say what the OAT was. I'd gather that it was above 0C.

I fly a PA28-180C (PP-SEL/Instrument). This past summer in severe
clear, 2 SMOH, I had a rough running engine and made a 180 and landed
right back at the airport I departed from (from about 10 min out). We
looked at everything and the only thing we could come up with was I had
gotten a load of ice (for those of you who have not flown this model,
the updraft carb attaches to the intake manifold which runs through the
middle of the oil pan -- difficult to get ice, but I managed).

In your case I am thinking that you need to pull and inspect your fuel
filters and/or screens. You may find them contaminated with water (or
perhaps some other foreign substance).

But then, just like in my case, static run ups, sumping fuel, etc.
shows nothing. And the plane runs just fine like it was all a figment
of your imagination.

As another person noted (being much more familiar with your model than
I am - I can only drool at the M20 parked over at the maint hanger),
you may have pockets in your tanks that allow for trapped water and by
luck of the draw...

BTW - This PA28-180C is the first I've owned. Used to fly rental
Cessnas which seemed to always have water. This one has to fly through
a serious rain storm to get any water. Seems it sucks it in through the
tank vents!

Later,
Steve.T