Engine failure

I think your mechanic was right. RPM has nothing to do with whether the
engine is getting gas. It will windmill at 800-900 RPM with the engine
off. I have seen this problem before. It is not extremely rare. An idle
check on runup should discover it, unless you finally managed to loosen
the throttle just enough on short final for it to finally stop working.

The reason I do not think it was carb ice is that the weather was below
freezing, which means that the air was probably relatively dry and it
may even have been too cold for carb ice to form (the air would have to
have liquid water precipitate out of it to cause carb ice, meaning that
the air would have to be warmed in the carburetor, not cooled, and
somehow also exceed 100% humidity in the process).

This is one reason many instructors are so dead set against their
students getting low on final. You can run out of options real fast,
and a disproportionate number of engine failures happen there.

Engines almost always fail just when you change something: throttle,
carb heat, mixture, prop, etc. There can be a lot wrong with an engine
and it will keep running if you never change anything, but a
configuration change will often be the last straw before she quits.
Before making any adjustments to an engine it is good practice to scan
the area for emergency landing fields.

"cjcampbell" wrote in message news:

This is one reason many instructors are so dead set against their
students getting low on final. You can run out of options real fast,
and a disproportionate number of engine failures happen there.

Evidence?


Engines almost always fail just when you change something: throttle,
carb heat, mixture, prop, etc. There can be a lot wrong with an engine
and it will keep running if you never change anything, but a
configuration change will often be the last straw before she quits.
Before making any adjustments to an engine it is good practice to scan
the area for emergency landing fields.

Power changes are taught as SOP for climbs and descents. If what you say is
true (and I don't know it isn't, but I doubt it) engine outs could be
reduced by climbing or descending without power changes. Or at least
deferred until landing.

moo

Carb ice, period!

If it was a fuel pump, mag, loose throttle stop, stuck lifters, etc.,
none of these things cure themselves after the engine stops. An iced
up air filter might melt off, but not in seconds... Carb ice is the one
thing that will clear within seconds inside of a warm engine once the
windmilling stops, which stops it pulling more cold air across the
venturi... . And a Lycoming will ice up... I had an engine on Fat
Albert go limp at 11,500 feet over top of the Detroit B on a winter
day, and it was 25 degrees at our altitude...
A few years back I lost an old high school classmate from Caro,
Michigan when he went for a student night flight in a Cherokee, iced up
and then stalled it before he got to the ground...

Claiming it couldn't be carb ice because it was too cold, dry, hot, up,
down, left, right, is wishful thinking.... In spring and fall get the
carb heat on early, lean it out aggressively before pulling the
throttle, and goose the engine every 20 seconds to keep it warm...

denny

In article .com,
"Denny" wrote:
venturi... . And a Lycoming will ice up... I had an engine on Fat
Albert go limp at 11,500 feet over top of the Detroit B on a winter
day, and it was 25 degrees at our altitude...

A Lycoming with the carb mounted to the oil pan will ice up, but it is
ironically more likely in cruise than in a low-power configuration. The
exceptions that I've seen involve extended power-off glides, and
extended taxis where the engine has not yet reached operating
temperature for the day.


JKG

This is about as clear as it can be described.

Tom

"Denny" wrote in message
oups.com...
Carb ice, period!

If it was a fuel pump, mag, loose throttle stop, stuck lifters, etc.,
none of these things cure themselves after the engine stops. An iced
up air filter might melt off, but not in seconds... Carb ice is the one
thing that will clear within seconds inside of a warm engine once the
windmilling stops, which stops it pulling more cold air across the
venturi... . And a Lycoming will ice up... I had an engine on Fat
Albert go limp at 11,500 feet over top of the Detroit B on a winter
day, and it was 25 degrees at our altitude...
A few years back I lost an old high school classmate from Caro,
Michigan when he went for a student night flight in a Cherokee, iced up
and then stalled it before he got to the ground...

Claiming it couldn't be carb ice because it was too cold, dry, hot, up,
down, left, right, is wishful thinking.... In spring and fall get the
carb heat on early, lean it out aggressively before pulling the
throttle, and goose the engine every 20 seconds to keep it warm...

denny

Carb heat was on for at least a minute or two (applied late downwind, and
the engine quit only in the flare on landing).

I'm not trying to say I know what caused it, just that I struggle to
understand how it could be carb ice with heat on, at prox freezing plus a
couple degrees, and with carb heat apparently working per runup indications.


"Denny" wrote in message
oups.com...
Carb ice, period!

If it was a fuel pump, mag, loose throttle stop, stuck lifters, etc.,
none of these things cure themselves after the engine stops. An iced
up air filter might melt off, but not in seconds... Carb ice is the one
thing that will clear within seconds inside of a warm engine once the
windmilling stops, which stops it pulling more cold air across the
venturi... . And a Lycoming will ice up... I had an engine on Fat
Albert go limp at 11,500 feet over top of the Detroit B on a winter
day, and it was 25 degrees at our altitude...
A few years back I lost an old high school classmate from Caro,
Michigan when he went for a student night flight in a Cherokee, iced up
and then stalled it before he got to the ground...

Claiming it couldn't be carb ice because it was too cold, dry, hot, up,
down, left, right, is wishful thinking.... In spring and fall get the
carb heat on early, lean it out aggressively before pulling the
throttle, and goose the engine every 20 seconds to keep it warm...

denny

Happy Dog wrote:

Power changes are taught as SOP for climbs and descents. If what you say is
true (and I don't know it isn't, but I doubt it) engine outs could be
reduced by climbing or descending without power changes. Or at least
deferred until landing.

That would be a neat trick. :-P

He did NOT say that the temperature was BELOW freezing, he said that the
temperature was ABOUT freezing, which is a prime candidate for carb ice. He
also mentioned nothing about visible moisture (clouds) which would be
another clue that the air DID contain sufficient moisture to cause carb ice.

And yes, engine restart on the taxiway after a dead stick iced carb is the
norm, as the engine compartment warms up with hot cylinders and no cold air
moving over them. Carb warms up REAL quick that way.

Jim


"cjcampbell" wrote in message
oups.com...


The reason I do not think it was carb ice is that the weather was below
freezing, which means that the air was probably relatively dry and it
may even have been too cold for carb ice to form (the air would have to
have liquid water precipitate out of it to cause carb ice, meaning that
the air would have to be warmed in the carburetor, not cooled, and
somehow also exceed 100% humidity in the process

In article ,
"RST Engineering" wrote:

He did NOT say that the temperature was BELOW freezing, he said that the
temperature was ABOUT freezing, which is a prime candidate for carb ice. He
also mentioned nothing about visible moisture (clouds) which would be
another clue that the air DID contain sufficient moisture to cause carb ice.

And yes, engine restart on the taxiway after a dead stick iced carb is the
norm, as the engine compartment warms up with hot cylinders and no cold air
moving over them. Carb warms up REAL quick that way.

Jim


"cjcampbell" wrote in message
oups.com...


The reason I do not think it was carb ice is that the weather was below
freezing, which means that the air was probably relatively dry and it
may even have been too cold for carb ice to form (the air would have to
have liquid water precipitate out of it to cause carb ice, meaning that
the air would have to be warmed in the carburetor, not cooled, and
somehow also exceed 100% humidity in the process

Loose nuts on the studs attaching the carburetor to the engine are NOT
all that uncommon! I have known of several. That will cause the engine
to stop at low power/idle settings!

Yes, but that engine is a bitch to restart and will quit as soon as you go
to idle. OP said that restart was easy and wouldn't quit again. I still
think it was carb ice.

Jim



"Orval Fairbairn" wrote in message
newsrfairbairn-

Loose nuts on the studs attaching the carburetor to the engine are NOT
all that uncommon! I have known of several. That will cause the engine
to stop at low power/idle settings!