Engine failure

Their theory was that it was carb ice.

Plane was a Dakota.

Interesting. If so, that's the first instance of carb icing I've heard
about with a Dakota.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:

Interesting. If so, that's the first instance of carb icing I've heard
about with a Dakota.

Lycomings rarely suffer from carb icing because the air intake is routed through
the oil sump on most models. This keeps the carb warm.

Unless, of course, you just started the engine a few minutes ago and the oil's
still cold.

As of two years ago, Shenandoah Valley impressed me as having a pretty competent
shop.

George Patterson
Drink is the curse of the land. It makes you quarrel with your neighbor.
It makes you shoot at your landlord. And it makes you miss him.

"Jase Vanover"

I taxied to the maintenance hanger (after being directed there by the FBO
via radio notification of the situation), and explained what happened to
the maintenance guy. He said that there is a stop on the throttle to keep
the idle setting from being too low that probably needed adjustment. Even
so, during shutdown (after restarting), idle setting on the throttle was
still 800 - 900 RPM, which should be enough to keep the engine running I
would think.

Anyone else experienced this and can share their thoughts? I'm about a 60
hour pilot, so not much experience.

Part of the run-up is a slow idle check. You should pull the throttle
fairly hard to see if the idle speed falls significantly below the spec'd
minimum. I don't know if that's what happened to you, but it's pretty
common.

I was flying into La Guardia on Air Canada and I saw a Bonanza rolling out
with the engine stopped. By total coincidence, exiting the plane, I got a
call from that pilot's instructor who'd briefed the pilot on this X/C. He
said that there was a known problem with that plane and, I think, said that
it was not an uncommon problem with that type of plane. Odd thing,
coincidence.

Anyway, engines quitting on final is an occasional story topic. There you
go...

moo

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

Here's instance #2 for ya Jay.

A Dakota on our field was owned by a VFR only pilot. Last summer on a trip
from STE to GRB and back, he reported having carb ice 3 times during his
trip. He questioned that it was really carb ice, but said that each time
the engine started to sputter, carb heat smoothed out the roughness in text
book fashion. Each time, the engine then ran smoothly for awhile then got
gradually rougher until carb heat was applied again.

I was at the airport when he returned and reported the problem to the
mechanic. To satisfy the pilot, the mechanic looked over the airplane and
found nothing wrong. It was simply the effect of a very humid day.

Jim

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!