Engine stoppage during idle

Why was the pump on and why were you at full rich?




Peter wrote:
IO-540-C4, Socata TB20

Just got this today. Landed, taxied off the runway, and before doing
the post-landing procedure (ie, with the mixture on full rich and the
fuel pump still running) noticed the revs to be very low, c. 500 and
then unsuprisingly the engine stopped.

Initially I suspected the idle setting had got moved. Did a start (hot
start, the usual lots of cranking) and all was fine. Idle is perfect
at 700rpm, just the way it was set up by a very good Socata engineer a
couple of years ago. Mag checks fine, EDM700 fine.

Nothing special about the conditions. OAT +19C, DP +15C, 1hr flight at
2000ft.

Enquiries suggest this sort of thing happens every once in a while.

I just haven't had it in 500+ landings in this aircraft, so it is
suprising.

Any views would be much appreciated.

I am considering having the fuel system inspected for
debris/blockages.

You're running way too rich.




Peter wrote:
Newps wrote


Why was the pump on and why were you at full rich?


Because that is how it is when one lands.

I have done some test runs today and found that the problem can be
repeated if one quite decisively pushes the throttle shut - that drops
the RPM from 700 to about 500. It happens only when the engine is
warm; say CHT of 330F or higher. The mixture doesn't really affect it.

So it seems OK, but I might inspect the throttle linkage anyway.

Well Peter, I don't know who is telling you to configure the engine
that way for landing but you may want to poll the big bore drivers on
here... I can tell you from experience with injected 360-520-540-720,
that many a hot engine will quit if used like that...
Personally, I leave the engine partially leaned in the landing
pattern...

denny

Peter wrote:
Newps wrote

Why was the pump on and why were you at full rich?

Because that is how it is when one lands.

Peter wrote:
"Denny" wrote


Well Peter, I don't know who is telling you to configure the engine
that way for landing but you may want to poll the big bore drivers on
here... I can tell you from experience with injected 360-520-540-720,
that many a hot engine will quit if used like that...
Personally, I leave the engine partially leaned in the landing
pattern...


I can see it both ways.

In the UK, the SOP is to go max-rpm and full-rich on short final, in
anticipation of a go-around.

That's SOP in the US, too. I've never heard of what Denny and Newps are
suggesting, but then I don't fly a big-bore, and don't keep up with
their SOPs.

Yes, sometimes this is necessary. Especially at high density
altitude.

--Dan



Denny wrote:
Well Peter, I don't know who is telling you to configure the engine
that way for landing but you may want to poll the big bore drivers on
here... I can tell you from experience with injected 360-520-540-720,
that many a hot engine will quit if used like that...
Personally, I leave the engine partially leaned in the landing
pattern...

denny

Peter wrote:
Newps wrote

Why was the pump on and why were you at full rich?

Because that is how it is when one lands.

There's two reasons not to go to full rich for landing. For me the most
important is density altitude. I live at 3650 msl and see lots of
flatlanders land full rich on a 90 degree day and have the engine quit
on rollout. Running full rich in these situations is just ****ing power
away when you need it. The second reason is fouling the plugs.



Dave Butler wrote:
Peter wrote:

"Denny" wrote


Well Peter, I don't know who is telling you to configure the engine
that way for landing but you may want to poll the big bore drivers on
here... I can tell you from experience with injected 360-520-540-720,
that many a hot engine will quit if used like that...
Personally, I leave the engine partially leaned in the landing
pattern...



I can see it both ways.
In the UK, the SOP is to go max-rpm and full-rich on short final, in
anticipation of a go-around.


That's SOP in the US, too. I've never heard of what Denny and Newps are
suggesting, but then I don't fly a big-bore, and don't keep up with
their SOPs.

"Dave Butler" wrote in message
...
Peter wrote:

In the UK, the SOP is to go max-rpm and full-rich on short final, in
anticipation of a go-around.

That's SOP in the US, too. I've never heard of what Denny and Newps are
suggesting, but then I don't fly a big-bore, and don't keep up with their
SOPs.

In a piston popper, of any size, the engine responds quickly enough that
full rich/RPM's is more damaging, unless you like lead fouling in your
engine.

--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO (MTJ)

"Newps" wrote in message
...
There's two reasons not to go to full rich for landing. For me the most
important is density altitude. I live at 3650 msl and see lots of
flatlanders land full rich on a 90 degree day and have the engine quit on
rollout. Running full rich in these situations is just ****ing power away
when you need it. The second reason is fouling the plugs.

Quite!
http://www.avweb.com/news/pelican/182085-1.html (last couple, three
paragraphs)


--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO (MTJ)

On 19-Sep-2006, Peter wrote:

I have done some test runs today and found that the problem can be
repeated if one quite decisively pushes the throttle shut - that drops
the RPM from 700 to about 500. It happens only when the engine is
warm; say CHT of 330F or higher. The mixture doesn't really affect it.

So it seems OK, but I might inspect the throttle linkage anyway.


This sure suggests that the problem lies with the throttle idle stop,
possibly a mechanical misalignment between the stop adjustment ant the cam
on the throttle control that is supposed to hit it. The misalignment may be
temperature related, i.e. the cam/stop orientation changes just a bit
between cold and hot conditions.

At any rate, if the engine otherwise runs fine this does not seem like a
serious problem.

-Elliott Drucker

On Wed, 20 Sep 2006 10:20:17 -0700, "Matt Barrow"
wrote:


"Newps" wrote in message
...
There's two reasons not to go to full rich for landing. For me the most
important is density altitude. I live at 3650 msl and see lots of
flatlanders land full rich on a 90 degree day and have the engine quit on
rollout. Running full rich in these situations is just ****ing power away
when you need it. The second reason is fouling the plugs.

Quite!
http://www.avweb.com/news/pelican/182085-1.html (last couple, three
paragraphs)

I'm learning to hate sites like this. I'm logged in via another route,
but it's not smart enough to know that when I follow this link.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com