Re: Engine stoppage during idle

[Newps]

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.

[Newps]

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.

[Denny]

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.
>

[Dave Butler[_1_]]

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.

[Dan[_1_]]

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.
> >

[Newps]

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.

[Matt Barrow]

"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)

[Matt Barrow]

"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)

[[email protected]]

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

[Roger (K8RI)]

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