Mt. Saint Helens

In article ,
Peter Duniho wrote:
"C J Campbell" wrote in message
...
[...] There is some evidence of a prehistoric volcanic explosion at
Yellowstone

Yellowstone is one huge caldera, almost certainly the remains of a large
erupted volcano. This is well-established geological fact.

that reduced the worldwide human population to fewer than a
dozen individuals

Never heard that one before. Fewer than 12 people remaining, around the
entire globe you say? Yeah, right. I doubt any scientist with an actual
clue believes that.

but that event has yet to be proven.

No kidding? I'm shocked.

I've never heard the less then a dozen people left, but one of
those Discovery Channel type shows awhile back was on using DNA
markers to trace how humans have moved around and interbred over
the years. One of the things they found was that at one point,
the human population was drastically reduced to ~10,000 people.

John
--
John Clear - http://www.panix.com/~jac

that reduced the worldwide human population to fewer than a
dozen individuals

Never heard that one before. Fewer than 12 people remaining, around the
entire globe you say? Yeah, right. I doubt any scientist with an actual
clue believes that.

Well, there *is* a certain well-documented story, very widely known
around the world, about a group of only 8 people left remaining after
a planet-wide calamity wiped out the rest of the human population, but
you probably don't believe that one either.

On Fri, 01 Oct 2004 02:20:25 GMT, Philip Sondericker
wrote:


I was thinking about this recently, and I was trying to determine exactly
what the effects would be on a small plane flying into an ash cloud. How
long would it take for the air filter to become completely clogged? And at
that point, assuming the plane had a carburetor, what would be the effect on
the engine? Would the plugs become fouled? Would they fire at all?

I'm a new pilot and relatively ignorant of engine operations, so I'm curious
to hear the answers.

I recall reading a first hand experience of exactly what you are
describing. Not positive but I think the pilot was flying an early
Cessna or perhaps a Luscombe or something similar. He was with his
wife and was flying downwind of Mt St Helens and unaware of the
explosion. He was either overtaken by the plume, or flew into it
thinking it was something else and was in immediate and serious
trouble.

He could not see hardly anything and ended up luckily overflying an
airfield on which he had to circle to land, in the otherworldly
darkness and lack of vision. His engine was barely running by this
time and he managed to bump it down and it quit instantly as he
touched down.

My recollection is that the airplane looked like it had been
sandblasted. The paint was gone from the leading edges of the wing
and anything facing into the wind. The windshield was opaque. The
prop was abraided, the air filter was clogged to the point where it
would not pass any air and I seem to remember engine damage.

I also recall him saying that he burst into tears upon getting out of
the airplane as he realised just how close things had been for him and
his wife.

Corky Scott

Corky Scott wrote:

On Fri, 01 Oct 2004 02:20:25 GMT, Philip Sondericker
wrote:

I was thinking about this recently, and I was trying to determine
exactly what the effects would be on a small plane flying into an ash
cloud.

I recall reading a first hand experience of exactly what you are
describing.

Hi Corky,

the story you related is in my memory as well. About ten years ago, I
used to read flying stories from a gopher server. This was called the
"rec.aviation archive". It had a collection of around 50 great stories,
among them the Mount St. Helens one. Unfortunately, I have been unable to
locate this information ever since. The closest I came was the following
old posting but the link in there does not work anymo
http://groups.google.com/groups?selm...ercury.mcs.com
Does anybody know a new location of the mentioned site?

There were some other gems among the stories, too. I recall vividly a
visit to a Concorde cockpit and the famous Cessna hijack story (still
online today at http://www.prime-mover.org/Personal/travis.txt).


Greetings,
Markus

Markus Voget wrote:

Corky Scott wrote:

On Fri, 01 Oct 2004 02:20:25 GMT, Philip Sondericker
wrote:

I was thinking about this recently, and I was trying to determine
exactly what the effects would be on a small plane flying into an ash
cloud.

I recall reading a first hand experience of exactly what you are
describing.

"rec.aviation archive". It had a collection of around 50 great
stories, among them the Mount St. Helens one. [...]
Does anybody know a new location of the mentioned site?

I found the stories again myself. Since they all seem to have originated
from a (nowadays unused) newsgroup they were still available on Google
Groups. If you go to
http://groups.google.com/groups?grou...iation.stories
(ignore everything younger than 1999) you can still read them. The
volcano story is this one:
http://groups.google.com/groups?selm...488%40peck.com


Greetings,
Markus

Philip Sondericker wrote in message ...
in article fT27d.3595$mS1.2578@fed1read05, BTIZ at
wrote on 9/30/04 7:00 PM:

that would be one heck of a thermal ride... if it weren't for the rocks...
and "cough cough" the ash..

BT

I was thinking about this recently, and I was trying to determine exactly
what the effects would be on a small plane flying into an ash cloud. How
long would it take for the air filter to become completely clogged? And at
that point, assuming the plane had a carburetor, what would be the effect on
the engine? Would the plugs become fouled? Would they fire at all?

I'm a new pilot and relatively ignorant of engine operations, so I'm curious
to hear the answers.


Flying through forest fire smoke can roast and asphyxiate you. I'm
assuming volcanic ash is just as hot if not hotter (but possibly with
more oxygen). The air filter and spark plugs will be the least of your
worries at that point : )

-lance smith

Philip Sondericker wrote in message ...
in article fT27d.3595$mS1.2578@fed1read05, BTIZ at
wrote on 9/30/04 7:00 PM:

that would be one heck of a thermal ride... if it weren't for the rocks...
and "cough cough" the ash..

BT

I was thinking about this recently, and I was trying to determine exactly
what the effects would be on a small plane flying into an ash cloud. How
long would it take for the air filter to become completely clogged? And at
that point, assuming the plane had a carburetor, what would be the effect on
the engine? Would the plugs become fouled? Would they fire at all?

I'm a new pilot and relatively ignorant of engine operations, so I'm curious
to hear the answers.
Phillip
If you were unlucky enough, or foolish enough to fly into a volcanic
ash cloud, your engine would probably quit within minutes. That is if
the turbulence, or heat, or other potential trash like huge boulders
isn't in there to get you first!
The ash would quickly plug the air filter choking out the airflow. The
ash would most likely corrode your windscreen to an opaque as well as
take off paint from the leading edges. The engine may quit entirely or
just run weakly. there are reports of jet aircraft that sucked up ash
cloud and destroyed the engines from the abrasive pumice they
ingested. Many people to the east of St Helens had some expensive
repairs to their vehicles after all the ash had settled. It was a
couple of feet deep in many places as far away as 90-100 miles in the
Columbia Basin and Moses Lake area.
A friend of mine was crop dusting east of St Helens in the Palouse
area, a day after it exploded, when he said the ash entered the
cockpit of the spray plane and he couldn't even see the panel! Only
many thousands of hours of experience saved him from crashing.
Oddly enough I was flying around St Helens about two weeks before it
blew up. Got some pics of the snow melting around the top of the
mountain. After I saw the eruption, I had to shake my head that I
wasn't flying over it then!! I did a lot of crop dusting in the WA/OR
area and some of it was on the south slopes of St Helen.

Ol shy & Bashful

(SelwayKid) wrote in message . com...
Philip Sondericker wrote in message ...
in article fT27d.3595$mS1.2578@fed1read05, BTIZ at
wrote on 9/30/04 7:00 PM:

that would be one heck of a thermal ride... if it weren't for the rocks...
and "cough cough" the ash..

BT

I was thinking about this recently, and I was trying to determine exactly
what the effects would be on a small plane flying into an ash cloud. How
long would it take for the air filter to become completely clogged? And at
that point, assuming the plane had a carburetor, what would be the effect on
the engine? Would the plugs become fouled? Would they fire at all?

I'm a new pilot and relatively ignorant of engine operations, so I'm curious
to hear the answers.
Phillip
If you were unlucky enough, or foolish enough to fly into a volcanic
ash cloud, your engine would probably quit within minutes. That is if
the turbulence, or heat, or other potential trash like huge boulders
isn't in there to get you first!
The ash would quickly plug the air filter choking out the airflow. The
ash would most likely corrode your windscreen to an opaque as well as
take off paint from the leading edges. The engine may quit entirely or
just run weakly. there are reports of jet aircraft that sucked up ash
cloud and destroyed the engines from the abrasive pumice they
ingested. Many people to the east of St Helens had some expensive
repairs to their vehicles after all the ash had settled. It was a
couple of feet deep in many places as far away as 90-100 miles in the
Columbia Basin and Moses Lake area.

Jet engines have almost no sliding parts exposed to incoming air.
Piston engines have many sliding parts, and ash or any other grit gets
between pistons and rings and cylinder walls and destroys them in
minutes. Grit will get past the piston and rings and foul the oil,
plugging the oil filter and causing the bypass to open, feeding gritty
oil to the pump and every bearing and gear. Alternator brushes and
vented mags would be in big trouble.
Tests on auto engines in the '80s by a piston ring manufacturer
found that a teaspoon of grit fed into a Chev 350 carb while running
near max power on a dyno would trash the engine in 5 minutes. No
compression, bearings gone, rattling madly. Anyone who deliberately
flies a lightplane into any ash cloud could be suspected of being
ignorant or insane.

A friend of mine was crop dusting east of St Helens in the Palouse
area, a day after it exploded, when he said the ash entered the
cockpit of the spray plane and he couldn't even see the panel! Only
many thousands of hours of experience saved him from crashing.

If the cockpit fills with ash, the central vacuum filter will plug
up quick, and there's no bypass to open. You'd lose all vacuum-powered
gyros; not the ideal situation in IMC.

Dan