Catastrophic Decompression; Small Place Solo

I would never have picked up on it, but the aviation magazines made a big
thing of it at the time.

Bob Gardner

"Robert Moore" wrote in message
. 8...
"Bob Gardner" wrote

This reminds me of the time when LearJet got a jet certified for 51,000
feet...the photograph in the aviation press showed both pilots smiling
into the camera at FL510 without an oxygen mask in sight. Always
wondered how the FAA reacted to that.

They probably had "quick donners" available, which modifies the reg.

Bob Moore

Aviation wrote:

Do they put their oxygen masks on FIRST or start the dive first?

Masks go on first. After the Payne Weber incident, there was some discussion about
instituting a policy whereby at least one of the flight crew is wearing a mask at all
times above a certain altitude. I don't know if that was emplemented. Crews would set
the autopilot to perform the descent even if they lose consciousness.

Someone also pointed out my goof about "holding" your breath
upon going from cabin (8000 ft pressure) to ambient (25-35,000
ft pressure). In estimating how much time the average civilian
passenger could go without TAKING a breath of good air (14,000
ft or below), I used the HOLD your breath estimate. Assuming
there is 3-5 minutes of mask-oxygen and one minute of "holding"
the last breath, they've got 3-6 minutes to get down to breathable
(14,000 ft?) air and then below.

Once again. You cannot hold the last breath for 1 minute. You can't hold it for five
seconds. The air will rush out of your lungs as rapidly as it rushes out of the
plane,
and there isn't a single thing you can do about it. As soon as the pressure gets
below
about 10 psi, the oxygen will start to leave your bloodstream. You have perhaps 45
seconds before you turn into a babbling idiot - probably much less. If they don't get
you down to a decent altitude in less than about 4 minutes, you may stay a babbling
idiot for the rest of your life. A few more minutes, and you will probably die.

For the movie Executive Decision,
they were cruising at 39,000 ft. so they'd have to dive 25,000 ft
to 14,000 ft in 5 minutes, 5,000 ft/minute, average. Doable?

Mike Rappaport posted that his aircraft can descend at 10,000 fpm. He also posted
the opinion that many jets can do better than that.

I found some rate of ASCENT data of about 3850 ft/min at
http://www.altairva-fs.com/fleet/poh...0747%20POH.htm
but descent data isn't clear to me but it looks like 2500 ft/min
from cruise altitude down to 10,000 ft is the recommended ROD.

Recommended descent rate goes out the window in an emergency. Think on it a little.
Most jet airliners top out between 400 and 500 mph. Idle the engines and point the
nose down, you should be able to get a rate of descent in excess of 25,000 fpm. Hit
500 knots straight down, and you're talking 50,000 fpm, but the pullout would
probably
pull the wings off.

The discussion of the ear problem seems unsettled. Upon going
from 8000 ft cabin pressure to 25000+ ft pressure in a couple
of seconds (if loss of pressure is total), some rapid swallowing
should equilibrate your ears to low pressure. Descending from
25,000+ (39,000) ft at 5,000 ft/min could result in reversible
or IRREVERSIBLE damage depending on a person's ability to
equilibrate REALLY fast.

If you have the presence of mind to do the exercises necessary to save your ears
when the pressure drops, perhaps you'd have the presence of mind to hold your
nose and blow into your ears on the way down? Even if you don't, it beats dying.

George Patterson
Great discoveries are not announced with "Eureka!". What's usually said is
"Hummmmm... That's interesting...."

On Wed, 31 Dec 2003 20:48:28 GMT,
(Aviation) wrote:


Someone also pointed out my goof about "holding" your breath
upon going from cabin (8000 ft pressure) to ambient (25-35,000
ft pressure). In estimating how much time the average civilian
passenger could go without TAKING a breath of good air (14,000
ft or below), I used the HOLD your breath estimate. Assuming
there is 3-5 minutes of mask-oxygen and one minute of "holding"
the last breath, they've got 3-6 minutes to get down to breathable
(14,000 ft?) air and then below. For the movie Executive Decision,
they were cruising at 39,000 ft. so they'd have to dive 25,000 ft
to 14,000 ft in 5 minutes, 5,000 ft/minute, average. Doable?

No, the length of time you can hold your breath on the ground doesn't
help. You will outgas O2 from your blood into your lungs and then
exhale it as part of your response to the RD, because the pressure
will be so greatly reduced. You will begin using the O2 mask with a
serious deficit and you'll continue to blow off O2, even with the
mask, until you get down to the altitude where the partial pressure is
large enough. Many people can't hold their breath for a minute,
either.

Airline pilots have quick-don masks that supply O2 at a higher rate
than do the cabin masks. The cockpit O2 is a separate supply from the
cabin O2, with more O2 at higher pressure. To be blunt, it's much
more important to keep the pilots conscious, of course.

Langeweische wrote, in his article about the ValuJet accident, that no
passenger had ever been saved by cabin O2. I don't know where he got
that information, but he's pretty good about checking statements like
that.

Mary

--
Mary Shafer Retired aerospace research engineer

"Mary Shafer" wrote in message
|
| Langeweische wrote, in his article about the ValuJet accident, that no
| passenger had ever been saved by cabin O2. I don't know where he got
| that information, but he's pretty good about checking statements like
| that.

He is probably right. At the altitudes airliners fly the partial pressure of
oxygen is too low to be absorbed by the bloodstream. You could fill the
entire cabin with pure oxygen and everybody would still suffocate. Those
little masks are not pressurized. Even if they were, the little elastic
thingies that hold the mask on would not maintain the required pressure. The
crew, of course, have pressurized masks.

On the other hand, it would take some time for people to start dying or
suffering permanent brain damage from lack of oxygen. The frail would be
most vulnerable, but a healthy passenger would at worst just pass out until
the airliner descended into breathable air.

"C J Campbell" wrote;

....... At the altitudes airliners fly the partial pressure of
oxygen is too low to be absorbed by the bloodstream. You could fill
the
entire cabin with pure oxygen and everybody would still suffocate.
Those
little masks are not pressurized.

If that were true, why would mountain climbers take little bottles of O2
with them when climbing Everest (and other 20K ft. and up mountains)?

--
Marc J. Zeitlin
http://marc.zeitlin.home.comcast.net/
http://www.cozybuilders.org/

"Marc J. Zeitlin" wrote in message
news_lJb.261887$_M.1216641@attbi_s54...
| "C J Campbell" wrote;
|
| ....... At the altitudes airliners fly the partial pressure of
| oxygen is too low to be absorbed by the bloodstream. You could fill
| the
| entire cabin with pure oxygen and everybody would still suffocate.
| Those
| little masks are not pressurized.
|
| If that were true, why would mountain climbers take little bottles of O2
| with them when climbing Everest (and other 20K ft. and up mountains)?
|

Airliners fly a lot higher than 20,000 feet. Those bottles are pressurized
and regulated as well. Climbers who use the oxygen usually only take a
breath or two when they need it. Although the masks are not very good, they
are better than the passenger masks on airliners. A lot of the oxygen is
still wasted, though. There are climbers who manage to make it up Everest
without any supplemental oxygen at all. Granted, they have had time to
acclimatize themselves, but even so it supports the idea that passengers are
not going to instantly die if the airplane depressurizes.

(Aviation) wrote in message du...
Thank you, everyone, for providing lots of helpful answers and info.

Even with slightly inaccurate info (2-seater; 6-seater), I guess
the second Q was easy:
Is the simplified movie solo flight completely
bogus or could it happen that way?

The basic answer is "more or less".

The answers to the first Q, being more tecnically compicated, leave
me asking for a few clarifications. That was about what REALLY happens
when a large pressurized aircraft, e.g., a 747, explosively or
catastrophically decompresses at high (25000+ feet) altitude.

Ron Natalie ) wrote:
On the one hand, passengers need to get denser air to breathe
but large aircraft have oxygen masks that drop down.

The pilots initiate the dive for the reasons you suggest. While
supplemental oxygen helps, it's still better to get down to a reasonable altitude. They presmably notify ATC while they are doing
this that there is an emergency in progress.

So, other than alarms or other signals, there is NOTHING AUTOMATIC
that puts the aircraft into rapid descent. Pilots have to respond
to the signals (explosion, screams from the cabin, meters in their
cockpit, their own ears popping, flashing lights, bells and whistles,
etc.) and initiate the dive MANUALLY. For well trained pilots this
would take, what, only a few seconds at most? Do they put their oxygen
masks on FIRST or start the dive first?

In some movies, the pilots are often unconscious, slumped over the
controls (wedging the 'steering wheel' / joystick full forward) as
the hero struggles to pull them out of the way and get out of the
dive. It sounds like a pilot, if not alert or in good health, could
actually lose consciousness from hypoxia under these conditions, so
maybe those kinds of movie scenes are ALMOST believable?

(This assumes worst case total decompression. It was pointed out
by Mike Rapoport ) that the cabin might
not even go to ambient pressure if the hole isn't too big and the
outflow valves close down and the engines keep pumping air into the
cabin.)

Someone also pointed out my goof about "holding" your breath
upon going from cabin (8000 ft pressure) to ambient (25-35,000
ft pressure). In estimating how much time the average civilian
passenger could go without TAKING a breath of good air (14,000
ft or below), I used the HOLD your breath estimate. Assuming
there is 3-5 minutes of mask-oxygen and one minute of "holding"
the last breath, they've got 3-6 minutes to get down to breathable
(14,000 ft?) air and then below. For the movie Executive Decision,
they were cruising at 39,000 ft. so they'd have to dive 25,000 ft
to 14,000 ft in 5 minutes, 5,000 ft/minute, average. Doable?

nope a person cannot simply hold ones breath. the pressure
differential between the airway cavity and the outside of the body
makes this impossible. in addition, a body of air expands and
contracts under pressure.

if anyone here is a certified diver they will be aware of compression
of air in the human body at depth (and the effects on ascent and
descent), and conversely the expansion of air at altitide.

When I conducted my first solo flight, it was pretty much a non-event
except that I had the plane to myself. After about thirty minutes of
dual - read that as two of us in the airplane, student (me) and the
instructor - including several landings at a controlled (has a tower)
airport, the instructor had me taxi over to the base of the tower and
shut the airplane down. He then asked for my log book and scribbled an
endorsement in the back certifying that I was qualified for solo flight.
Mind you, I had already received ten hours of flight training up to that
point plus extensive text work as well. He then told me to keep the
airplane "in the pattern", i.e. don't leave the controlled airspace
surrounding the airport: approximately a five mile radius. I was then
to perform three "touch and goes" - landings in which you place the
airplane on the runway but do not come to a stop but rather retract the
flaps while still rolling, apply power, and takeoff again. Then I was
to land with a full stop and return to the tower. He said he would
watch with the controllers. Geez, now I had an audience. I contacted
the tower via radio and was given clearance to takeoff and stay in the
pattern. I remembered I was literally shaking, not with fear but with
exhilaration. "Don't screw this up, don't screw this up," was my
mantra. I advanced the throttle once I was positioned on the centerline
of the runway and, in my estimation, the little Cessna 152 leapt
forward, unencumbered by the weight of a second person. Reaching 50
knots, I gently pulled back on the yoke and the plane rotated and
departed the runway. "WOW! I was flying! Really flying! I was in
control! I am a pilot!"
It was all I could do to not start whistling the theme from "The High
and the Mighty." The rest is history. Many hundreds and hundreds of
flight hours (PIC or Pilot In Command) later and innummerable aircraft,
I find myself grounded due to diabetes. Nothing will ever quite compare
to that first solo flight. God I miss it. Jerry


Aviation wrote:
I have two questions inspired by Hollywood movies.

In the movies (Goldfinger, Executive Decision and so on),
when pressurized aircraft suffer catastrophic decompression
at high (25000+ feet) altitude (usually when the bad guy
shoots a bullet through a window) everything not tied down
gets sucked out of the plane and the aircraft goes into an
immediate, rapid nose dive and the pilots or the good guys
have to struggle to level it off or prevent a crash.

Is this an automatic "safety" feature of real, regular aircraft?
On the one hand, passengers need to get denser air to breathe
but large aircraft have oxygen masks that drop down. (I could
do some rough estimates that the average fat slob can hold
their breath for less than a minute so, without masks, the jet
would have to go from let's say 30000 feet to 5000 feet in
30-45 seconds. My ears would explode.)

I would think that a crash dive to a lower altitude could be
even more dangerous such as if it occurred in a crowded air
corridor. Maybe there are other dangers.

What REALLY happens (or is supposed to happen) in the event
of sudden decompression of real high flying aircraft?



The second Hollywood inspired question comes from Executive
Decision (1996). The main character is taking flying lessons
in a single prop 2-seater plane and lands. The plane is still
running (on the ground) and his instructor says, 'I think
you're ready to solo' and gets out. The main character starts
to taxi and then other non-flying plot developments happen.
I was wondering if taking your FIRST solo flight is that simple.

The location in the film in Washington, DC but I figure all
US flying is FAA regulated. Wouldn't the first time soloist
have to fill out some forms, file a flight plan with the
airport and maybe even do a complete pre-flight check on the
aircraft? Is the simplified movie solo flight completely
bogus or could it happen that way?


THANK YOU VERY MUCH.

"Jerry Hall" wrote in message
...
When I conducted my first solo flight, it was pretty much a non-event
except that I had the plane to myself. After about thirty minutes of
dual - read that as two of us in the airplane, student (me) and the
instructor - including several landings at a controlled (has a tower)
airport, the instructor had me taxi over to the base of the tower and shut
the airplane down. He then asked for my log book and scribbled an
endorsement in the back certifying that I was qualified for solo flight.
Mind you, I had already received ten hours of flight training up to that
point plus extensive text work as well. He then told me to keep the
airplane "in the pattern", i.e. don't leave the controlled airspace
surrounding the airport: approximately a five mile radius. I was then to
perform three "touch and goes" - landings in which you place the airplane
on the runway but do not come to a stop but rather retract the flaps while
still rolling, apply power, and takeoff again. Then I was to land with a
full stop and return to the tower. He said he would watch with the
controllers. Geez, now I had an audience. I contacted the tower via
radio and was given clearance to takeoff and stay in the pattern. I
remembered I was literally shaking, not with fear but with exhilaration.
"Don't screw this up, don't screw this up," was my mantra. I advanced the
throttle once I was positioned on the centerline of the runway and, in my
estimation, the little Cessna 152 leapt forward, unencumbered by the
weight of a second person. Reaching 50 knots, I gently pulled back on the
yoke and the plane rotated and departed the runway. "WOW! I was flying!
Really flying! I was in control! I am a pilot!"
It was all I could do to not start whistling the theme from "The High and
the Mighty." The rest is history.

Many hundreds and hundreds of flight hours (PIC or Pilot In Command) later
and innummerable aircraft, I find myself grounded due to diabetes.

Have you thought about getting a special issuance (if your diabetes is under
fairly good control) to get your medical back and start flying again? :-)

Nothing will ever quite compare to that first solo flight. God I miss it.
Jerry


Aviation wrote:
I have two questions inspired by Hollywood movies.

In the movies (Goldfinger, Executive Decision and so on), when
pressurized aircraft suffer catastrophic decompression
at high (25000+ feet) altitude (usually when the bad guy shoots a bullet
through a window) everything not tied down gets sucked out of the plane
and the aircraft goes into an immediate, rapid nose dive and the pilots
or the good guys have to struggle to level it off or prevent a crash. Is
this an automatic "safety" feature of real, regular aircraft? On the one
hand, passengers need to get denser air to breathe but large aircraft
have oxygen masks that drop down. (I could do some rough estimates that
the average fat slob can hold their breath for less than a minute so,
without masks, the jet
would have to go from let's say 30000 feet to 5000 feet in 30-45 seconds.
My ears would explode.)

I would think that a crash dive to a lower altitude could be even more
dangerous such as if it occurred in a crowded air corridor. Maybe there
are other dangers.

What REALLY happens (or is supposed to happen) in the event
of sudden decompression of real high flying aircraft? The second
Hollywood inspired question comes from Executive
Decision (1996). The main character is taking flying lessons
in a single prop 2-seater plane and lands. The plane is still
running (on the ground) and his instructor says, 'I think you're ready to
solo' and gets out. The main character starts to taxi and then other
non-flying plot developments happen. I was wondering if taking your
FIRST solo flight is that simple. The location in the film in
Washington, DC but I figure all
US flying is FAA regulated. Wouldn't the first time soloist have to fill
out some forms, file a flight plan with the airport and maybe even do a
complete pre-flight check on the aircraft? Is the simplified movie solo
flight completely bogus or could it happen that way?


THANK YOU VERY MUCH.

John. It seems that once you move from oral medication to insulin as a
treatment for diabetes, that is the death knell to one's medical
certificate. Lord knows I've certainly jumped through a lot of hoops.
Several years ago the FAA medical folks as much as said, "Give it up,
turkey. You're not getting your medical reinstated." I go through a
similar line of BS in keeping my automobile driver's license. And my
glucose readings seldom go over 140. Have been hoping the newer "Sport"
license might allow me to fly again. Then there are ultralights but
that just isn't quite the same thing. To steal a line from Top Gun, I
feel the need for speed. Had a 177 RG. Jerry

John E. Carty wrote:
"Jerry Hall" wrote in message
...

When I conducted my first solo flight, it was pretty much a non-event
except that I had the plane to myself. After about thirty minutes of
dual - read that as two of us in the airplane, student (me) and the
instructor - including several landings at a controlled (has a tower)
airport, the instructor had me taxi over to the base of the tower and shut
the airplane down. He then asked for my log book and scribbled an
endorsement in the back certifying that I was qualified for solo flight.
Mind you, I had already received ten hours of flight training up to that
point plus extensive text work as well. He then told me to keep the
airplane "in the pattern", i.e. don't leave the controlled airspace
surrounding the airport: approximately a five mile radius. I was then to
perform three "touch and goes" - landings in which you place the airplane
on the runway but do not come to a stop but rather retract the flaps while
still rolling, apply power, and takeoff again. Then I was to land with a
full stop and return to the tower. He said he would watch with the
controllers. Geez, now I had an audience. I contacted the tower via
radio and was given clearance to takeoff and stay in the pattern. I
remembered I was literally shaking, not with fear but with exhilaration.
"Don't screw this up, don't screw this up," was my mantra. I advanced the
throttle once I was positioned on the centerline of the runway and, in my
estimation, the little Cessna 152 leapt forward, unencumbered by the
weight of a second person. Reaching 50 knots, I gently pulled back on the
yoke and the plane rotated and departed the runway. "WOW! I was flying!
Really flying! I was in control! I am a pilot!"
It was all I could do to not start whistling the theme from "The High and
the Mighty." The rest is history.


Many hundreds and hundreds of flight hours (PIC or Pilot In Command) later
and innummerable aircraft, I find myself grounded due to diabetes.


Have you thought about getting a special issuance (if your diabetes is under
fairly good control) to get your medical back and start flying again? :-)


Nothing will ever quite compare to that first solo flight. God I miss it.
Jerry


Aviation wrote:

I have two questions inspired by Hollywood movies.

In the movies (Goldfinger, Executive Decision and so on), when
pressurized aircraft suffer catastrophic decompression
at high (25000+ feet) altitude (usually when the bad guy shoots a bullet
through a window) everything not tied down gets sucked out of the plane
and the aircraft goes into an immediate, rapid nose dive and the pilots
or the good guys have to struggle to level it off or prevent a crash. Is
this an automatic "safety" feature of real, regular aircraft? On the one
hand, passengers need to get denser air to breathe but large aircraft
have oxygen masks that drop down. (I could do some rough estimates that
the average fat slob can hold their breath for less than a minute so,
without masks, the jet
would have to go from let's say 30000 feet to 5000 feet in 30-45 seconds.
My ears would explode.)

I would think that a crash dive to a lower altitude could be even more
dangerous such as if it occurred in a crowded air corridor. Maybe there
are other dangers.

What REALLY happens (or is supposed to happen) in the event
of sudden decompression of real high flying aircraft? The second
Hollywood inspired question comes from Executive
Decision (1996). The main character is taking flying lessons
in a single prop 2-seater plane and lands. The plane is still
running (on the ground) and his instructor says, 'I think you're ready to
solo' and gets out. The main character starts to taxi and then other
non-flying plot developments happen. I was wondering if taking your
FIRST solo flight is that simple. The location in the film in
Washington, DC but I figure all
US flying is FAA regulated. Wouldn't the first time soloist have to fill
out some forms, file a flight plan with the airport and maybe even do a
complete pre-flight check on the aircraft? Is the simplified movie solo
flight completely bogus or could it happen that way?


THANK YOU VERY MUCH.