Head Scratcher

("john smith" wrote)
This happened two days ago in Central Ohio. The pilot had just purchased
the 1966 Mooney M20F and was getting on a check out flight with the
instructor. Witnesses report the aircraft came straight down.


I read a link (in rec.aviation) a while back about a person investigating
the possibility that CO poisoning might be a culprit in more crashes than
people realize. Sounds like an interesting theory, except for my thought
that there were toxicology tests for that. Maybe his theory is they're not
catching it - forensically. Memory fails me on the details of the research
in the link.

I know some past exhaust issues have involved higher pressure vs. lower
pressure areas - Piper's tail cone 'low pressure zone' was one problem spot
for CO gas to find its way into the cabin, IIRC.

I know many planes are leaky ...but if you do have a somewhat tight cockpit,
would a (small) fresh air feed, slightly pressurizing the cabin (perhaps
with a small computer type fan), be good insurance against CO gas intrusion?


Montblack

Montblack wrote:

("john smith" wrote)


This happened two days ago in Central Ohio. The pilot had just purchased
the 1966 Mooney M20F and was getting on a check out flight with the
instructor. Witnesses report the aircraft came straight down.



I read a link (in rec.aviation) a while back about a person investigating
the possibility that CO poisoning might be a culprit in more crashes than
people realize. Sounds like an interesting theory, except for my thought
that there were toxicology tests for that. Maybe his theory is they're not
catching it - forensically. Memory fails me on the details of the research
in the link.

I know some past exhaust issues have involved higher pressure vs. lower
pressure areas - Piper's tail cone 'low pressure zone' was one problem spot
for CO gas to find its way into the cabin, IIRC.

I know many planes are leaky ...but if you do have a somewhat tight cockpit,
would a (small) fresh air feed, slightly pressurizing the cabin (perhaps
with a small computer type fan), be good insurance against CO gas intrusion?

You mean like this, for example...

CINCINNATI COUPLE
Cockpit fumes knock out pair while plane taxiing
Saturday, December 30, 2006
ASSOCIATED PRESS

A small plane drove off a taxiway at a northeastern Indiana airport
before takeoff after the pilot and passenger, both of Cincinnati,
apparently were overcome by fumes.

Others at the Delaware County Airport in Muncie, Ind., pulled Thomas and
Marilyn Kroll from the plane Wednesday night. They were unconscious and
taken to a hospital.

Gene Marlin, the pilot of a nearby plane, drove his plane up to the
Krolls’ aircraft.

"Whenever I got there, the line-boy had the door open but the gentleman
and the lady were still in the airplane and the airplane was running,"
Marlin told Indianapolis television station WTHR. "I just shut the
engine off and pulled the people from the airplane out."

Marlin said neither person regained consciousness before emergency crews
took them.

"The way the glass on the inside of the cockpit was all steamed up ...
it was all kind of glazed over, but it wasn’t ice. And the smell," he
said. "The fumes were real strong in there."

The Krolls were taken by helicopter to Wishard Memorial Hospital in
Indianapolis. Marilyn Kroll was listed in serious condition and Thomas
Kroll was in fair condition.

"Montblack" wrote

I know many planes are leaky ...but if you do have a somewhat tight
cockpit, would a (small) fresh air feed, slightly pressurizing the cabin
(perhaps with a small computer type fan), be good insurance against CO gas
intrusion?

Somewhat tight is the key phrase. I don't think most are tight enough for a
muffin fan to be able to create positive pressure.

Add to that, fan blade type fans are very, very poor at creating pressure.
Squirrel cage blowers are used where pressure is needed. That is why house
air handlers (furnaces) have squirrel cage blowers, as do heater blowers in
cars.

Still, a fresh air blower will not help where the cause of the CO is a
cracked heat exchanger. (muff)

The other problems are fixed by sealing off the leaks, especially in low
pressure areas, but you knew that.
--
Jim in NC

The pressure inside of the fuselage at speed will always be lower than the ambient outside air pressure. A ram air
source out on the wing and away from the engine compartment can provide fresh air, but a little muffin fan will not do
it. Does everyone have a CO monitor on board?



"Morgans" wrote in message ...
:
: "Montblack" wrote
:
: I know many planes are leaky ...but if you do have a somewhat tight
: cockpit, would a (small) fresh air feed, slightly pressurizing the cabin
: (perhaps with a small computer type fan), be good insurance against CO gas
: intrusion?
:
: Somewhat tight is the key phrase. I don't think most are tight enough for a
: muffin fan to be able to create positive pressure.
:
: Add to that, fan blade type fans are very, very poor at creating pressure.
: Squirrel cage blowers are used where pressure is needed. That is why house
: air handlers (furnaces) have squirrel cage blowers, as do heater blowers in
: cars.
:
: Still, a fresh air blower will not help where the cause of the CO is a
: cracked heat exchanger. (muff)
:
: The other problems are fixed by sealing off the leaks, especially in low
: pressure areas, but you knew that.
: --
: Jim in NC
:
:

Blueskies writes:

The pressure inside of the fuselage at speed will always be lower
than the ambient outside air pressure.

Really? Why?

--
Transpose mxsmanic and gmail to reach me by e-mail.