Turbo 182: correct mixture for final approach at high altitude?

Rick Durden wrote:
Otherwise, the only reason to enrichen the mixture during descent is
if the engine actually begins to run roughly. (See the POH which only
recommends enrichening if you experience engine roughness.) Most
people descend at 65% power or less, which means that it is impossible
to detonate the engine due to lack of heat and pressure, so it's
impossible to run it too lean (it will simply start to run rough and
then quit if you get it too lean, you won't hurt anything). Keeping
it leaned during descent helps avoid overcooling (if you believe in
shock cooling), helps keep the plugs from fouling and doesn't waste
fuel. In general, once you lean the engine for cruise on a T182 you
needn't touch the mixture control until you pull it to idle cutoff
after landing, or to go to full rich on a go around.

All the best,
Rick

The POH for my TB-21 (turbocharged Trinidad) with a
Lycoming TIO-540 calls for putting the mixture full rich
prior to landing. Is that different from what most people
do with this engine?

--
David Rind

"David Rind" wrote in message
...
The POH for my TB-21 (turbocharged Trinidad) with a
Lycoming TIO-540 calls for putting the mixture full rich
prior to landing. Is that different from what most people
do with this engine?

What actual model engine does the TB-21 have? Just knowing that it's a
TIO-540 doesn't give us enough information to compare with our own engines.

The engine in my plane, a TIO-540-AA1AD, cannot stay running at full rich at
idle at high density altitudes, as I mentioned in another post. I put the
mixture to full rich before landing only when landing below 3000' or so (and
then only so that I am more prepared for a go-around...operationally, I wind
up leaning again after leaving the runway so that the plugs don't foul).

Pete

Peter Duniho wrote:
What actual model engine does the TB-21 have? Just knowing that it's a
TIO-540 doesn't give us enough information to compare with our own engines.

TIO-540-AB1AD

--
David Rind

David,

I believe your POH does call for full rich prior to landing (but not
in the descent) in preparation for a possible go around. Otherwise,
there is no reason to enrichen it.

At very high altitude airports, landing with full rich mixture may
cause a rough idle or the engine may actually quit at the end of
rollout, but that depends on the idle mixture adjustment on your
engine.

If your engine runs fine at full rich at low power settings on the
ground, then there is no problem with going to full rich on final in
preparation for a go around. However, you may want to lean it while
taxiing (lean it a long ways so that it will simply quit should you
try to take off prior to going to full rich and it will remind you) so
as to help avoid plug fouling.

All the best,
Rick

David Rind wrote in message ...
Rick Durden wrote:
Otherwise, the only reason to enrichen the mixture during descent is
if the engine actually begins to run roughly. (See the POH which only
recommends enrichening if you experience engine roughness.) Most
people descend at 65% power or less, which means that it is impossible
to detonate the engine due to lack of heat and pressure, so it's
impossible to run it too lean (it will simply start to run rough and
then quit if you get it too lean, you won't hurt anything). Keeping
it leaned during descent helps avoid overcooling (if you believe in
shock cooling), helps keep the plugs from fouling and doesn't waste
fuel. In general, once you lean the engine for cruise on a T182 you
needn't touch the mixture control until you pull it to idle cutoff
after landing, or to go to full rich on a go around.

All the best,
Rick

The POH for my TB-21 (turbocharged Trinidad) with a
Lycoming TIO-540 calls for putting the mixture full rich
prior to landing. Is that different from what most people
do with this engine?

Rick Durden wrote:
David,

I believe your POH does call for full rich prior to landing (but not
in the descent) in preparation for a possible go around. Otherwise,
there is no reason to enrichen it.

At very high altitude airports, landing with full rich mixture may
cause a rough idle or the engine may actually quit at the end of
rollout, but that depends on the idle mixture adjustment on your
engine.

If your engine runs fine at full rich at low power settings on the
ground, then there is no problem with going to full rich on final in
preparation for a go around. However, you may want to lean it while
taxiing (lean it a long ways so that it will simply quit should you
try to take off prior to going to full rich and it will remind you) so
as to help avoid plug fouling.

All the best,
Rick

Thanks! So then if I think I'm capable of remembering to push
in the mixture on a go around there is really no need to enrich
the mixture prior to landing. FWIW, I'm good about aggressively
leaning once I'm off the runway.

--
David Rind