Catastrophic Decompression; Small Place Solo

"Scott M. Kozel" wrote in message ...
Dr. George O. Bizzigotti wrote:

"G.R. Patterson III" wrote:

Basically, the pilots need to get their masks on and get the plane down below
25,000' as rapidly as it can possibly be done. The descent to 10,000' can be made
a little more leisurely, but not much - there's always someone in the cattle
section who panicked and isn't wearing a mask.

One aspect that I have not seen addressed in this thread is the fact
that most oxygen systems can provide supplemental oxygen for a few
minutes only (I dimly recall figures like 3-5 minutes, but that may be
inaccurate). The pilots also need to get down to 10,000 feet within
that time before everyone's oxygen generators run out.

How could an SST like the Concorde get from cruising altitude down to
10,000 feet in 3-5 minutes?


emergency descent, throttles set, dirty up, hold pitch. regularly
practiced procedure. the express elevator down.

"Dr. George O. Bizzigotti" wrote in message
...
|
| One aspect that I have not seen addressed in this thread is the fact
| that most oxygen systems can provide supplemental oxygen for a few
| minutes only (I dimly recall figures like 3-5 minutes, but that may be
| inaccurate). The pilots also need to get down to 10,000 feet within
| that time before everyone's oxygen generators run out.
|

It really does not matter. The worst that will happen is that some people
will pass out, but it would be life threatening only to a very frail person.
As the airplane descends the time of useful consciousness increases rapidly,
so that oxygen would really only be needed for the first few minutes of
descent.

Dr. George O. Bizzigotti wrote in message . ..
On Tue, 30 Dec 2003 19:43:55 -0800, "G.R. Patterson III"
wrote:

Aviation wrote:

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

[snip]

As for your ears, they're already toast. The pressure just dropped
from the pressure at 8,000' to that at cruise altitude in a few seconds.

Based on what others have written about chamber simulations, it would
appear that irreversible ear damage (which is what I would infer as
being "toast") is not an inevitable consequence, although. I've no
doubt that the sensation from any reversible consequences is not
always pleasant .

Basically, the pilots need to get their masks on and get the plane down below
25,000' as rapidly as it can possibly be done. The descent to 10,000' can be made
a little more leisurely, but not much - there's always someone in the cattle
section who panicked and isn't wearing a mask.

One aspect that I have not seen addressed in this thread is the fact
that most oxygen systems can provide supplemental oxygen for a few
minutes only (I dimly recall figures like 3-5 minutes, but that may be
inaccurate). The pilots also need to get down to 10,000 feet within
that time before everyone's oxygen generators run out.

Regards,

nope. supplemental oxygen depends on the capacity of the resevoir, the
flow, the delivery system in use and of course the demands on this
(load) the requirements are in the FAR's.

23.1441 thru 23.1449
25.1441 thru 25.1449
121.327 thru 121.337
125.219
135.89 thru 135.91
135.157

"G.R. Patterson III" wrote in message

If the aircraft is much above 25,000', the masks will do little good. You
need
a pressure mask to survive long at (for example) 35,000'. Those used by
the
airlines for passengers are not good enough for that.

Passenger masks generally only need to provide sustenance for a couple of
minutes.

....the jet would have to go from let's say 30000 feet to 5000 feet in
30-45 seconds. My ears would explode.)

Basically, the pilots need to get their masks on and get the plane down
below
25,000' as rapidly as it can possibly be done. The descent to 10,000' can
be made
a little more leisurely, but not much - there's always someone in the
cattle
section who panicked and isn't wearing a mask. If that's one of the flight
attendants, you're really in trouble.

Ten thousand is where supplemental O2 is no longer legally required. In
reality, you're back in survivable atmosphere, for most people, at about
14,000 or so. Emergency descent procedures are predicated on descending
from cruise altitude to 10,000 MSL (or an altitude where you can maintain a
cabin alt of 10K) as rapidly as is safely possible. As a practical matter,
you won't be descending at much over 12-15 thousand f/m or so, so the
descent will take a minute and a half or more.

"John Gaquin" wrote in message ...
"G.R. Patterson III" wrote in message

If the aircraft is much above 25,000', the masks will do little good. You
need
a pressure mask to survive long at (for example) 35,000'. Those used by
the
airlines for passengers are not good enough for that.

Passenger masks generally only need to provide sustenance for a couple of
minutes.

....the jet would have to go from let's say 30000 feet to 5000 feet in
30-45 seconds. My ears would explode.)

Basically, the pilots need to get their masks on and get the plane down
below
25,000' as rapidly as it can possibly be done. The descent to 10,000' can
be made
a little more leisurely, but not much - there's always someone in the
cattle
section who panicked and isn't wearing a mask. If that's one of the flight
attendants, you're really in trouble.

Ten thousand is where supplemental O2 is no longer legally required. In
reality, you're back in survivable atmosphere, for most people, at about
14,000 or so. Emergency descent procedures are predicated on descending
from cruise altitude to 10,000 MSL (or an altitude where you can maintain a
cabin alt of 10K) as rapidly as is safely possible. As a practical matter,
you won't be descending at much over 12-15 thousand f/m or so, so the
descent will take a minute and a half or more.


FAR 91.211
Supplemental oxygen.
(a) General. No person may operate a civil aircraft of U.S. registry -
(1) At cabin pressure altitudes above 12,500 feet (MSL) up to and
including 14,000 feet (MSL) unless the required minimum flight crew is
provided with and uses supplemental oxygen for that part of the flight
at those altitudes that is of more than 30 minutes duration;
(2) At cabin pressure altitudes above 14,000 feet (MSL) unless the
required minimum flight crew is provided with and uses supplemental
oxygen during the entire flight time at those altitudes; and
(3) At cabin pressure altitudes above 15,000 feet (MSL) unless each
occupant of the aircraft is provided with supplemental oxygen.
(b) Pressurized cabin aircraft.
(1) No person may operate a civil aircraft of U.S. registry with a
pressurized cabin -
(i) At flight altitudes above flight level 250 unless at least a
10-minute supply of supplemental oxygen, in addition to any oxygen
required to satisfy paragraph (a) of this section, is available for
each occupant of the aircraft for use in the event that a descent is
necessitated by loss of cabin pressurization; and
(ii) At flight altitudes above flight level 350 unless one pilot at
the controls of the airplane is wearing and using an oxygen mask that
is secured and sealed and that either supplies oxygen at all times or
automatically supplies oxygen whenever the cabin pressure altitude of
the airplane exceeds 14,000 feet (MSL), except that the one pilot need
not wear and use an oxygen mask while at or below flight level 410 if
there are two pilots at the controls and each pilot has a
quick-donning type of oxygen mask that can be placed on the face with
one hand from the ready position within 5 seconds, supplying oxygen
and properly secured and sealed.
(2) Notwithstanding paragraph (b)(1)(ii) of this section, if for any
reason at any time it is necessary for one pilot to leave the controls
of the aircraft when operating at flight altitudes above flight level
350, the remaining pilot at the controls shall put on and use an
oxygen mask until the other pilot has returned to that crewmember's
station.

135.89
ilot requirements: Use of oxygen.
(a) Unpressurized aircraft. Each pilot of an unpressurized aircraft
shall use oxygen continuously when flying -
(1) At altitudes above 10,000 feet through 12,000 feet MSL for that
part of the flight at those altitudes that is of more than 30 minutes
duration; and
(2) Above 12,000 feet MSL.
(b) Pressurized aircraft.
(1) Whenever a pressurized aircraft is operated with the cabin
pressure altitude more than 10,000 feet MSL, each pilot shall comply
with paragraph (a) of this section.
(2) Whenever a pressurized aircraft is operated at altitudes above
25,000 feet through 35,000 feet MSL, unless each pilot has an approved
quick donning type oxygen mask -
(i) At least one pilot at the controls shall wear, secured and sealed,
an oxygen mask that either supplies oxygen at all times or
automatically supplies oxygen whenever the cabin pressure altitude
exceeds 12,000 feet MSL; and
(ii) During that flight, each other pilot on flight deck duty shall
have an oxygen mask, connected to an oxygen supply, located so as to
allow immediate placing of the mask on the pilot's face sealed and
secured for use.
(3) Whenever a pressurized aircraft is operated at altitudes above
35,000 feet MSL, at least one pilot at the controls shall wear,
secured and sealed, an oxygen mask required by paragraph (b)(2)(i) of
this section.
(4) If one pilot leaves a pilot duty station of an aircraft when
operating at altitudes above 25,000 feet MSL, the remaining pilot at
the controls shall put on and use an approved oxygen mask until the
other pilot returns to the pilot duty station of the aircraft.

"running with scissors" wrote in
message
FAR 91.211
Supplemental oxygen.

????

The FAA has opportunities for a chamber ride to actually experience rapid
decompression, and we have to do it periodically in the Air Force while on
flying status. On of our classmates volunteered to take off his oxygen mask
at 25,000 feet. He turned green immediately and started seizing, and despite
being prepared, he was unable to gang load his oxygen regulator and put his
mask back on. I wonder how many brain cells he killed.

The rapid decompression was pretty uneventful- there was kind of a loud pop,
and a lot of fog. This is the result of condensation due to cooling of the
air from expansion, not moisture from our bodies.

If you ate a lot of Mexican food the night before the pain from the gas
expanding comes on the ascent, not on the descent. Likewise, ear blocks
(feels like sticking an ice pick in your ear from personal experience) comes
during descent only, as the increased ambient pressure pushes inward on your
ear drum.

The most valuable part of the ride was the ability to recognize symptoms of
hypoxia, like decreased color vision, etc. A

Anyone who ever flies over 10,000 feet (or less at night) should consider a
chamber ride a valuable and potentially life saving experience.

Gotta admit that I am working from memory of events many long years ago and
may easily have screwed up the details. With regard to the fog, however,
there has to be moisture from somewhere...simple expansion is not the whole
story. Fog is, after all, a gazillion eensy-teensy droplets.

Bob

"Viperdoc" wrote in message
...
The FAA has opportunities for a chamber ride to actually experience rapid
decompression, and we have to do it periodically in the Air Force while on
flying status. On of our classmates volunteered to take off his oxygen
mask
at 25,000 feet. He turned green immediately and started seizing, and
despite
being prepared, he was unable to gang load his oxygen regulator and put
his
mask back on. I wonder how many brain cells he killed.

The rapid decompression was pretty uneventful- there was kind of a loud
pop,
and a lot of fog. This is the result of condensation due to cooling of the
air from expansion, not moisture from our bodies.

If you ate a lot of Mexican food the night before the pain from the gas
expanding comes on the ascent, not on the descent. Likewise, ear blocks
(feels like sticking an ice pick in your ear from personal experience)
comes
during descent only, as the increased ambient pressure pushes inward on
your
ear drum.

The most valuable part of the ride was the ability to recognize symptoms
of
hypoxia, like decreased color vision, etc. A

Anyone who ever flies over 10,000 feet (or less at night) should consider
a
chamber ride a valuable and potentially life saving experience.

"Bob Gardner" wrote in message news:JXDIb.16018

....With regard to the fog, however,
there has to be moisture from somewhere...simple expansion is not the
whole
story.

There is some moisture in the pressurization air pumped into the cabin, but
not much. More is absorbed from the bodies on board and evaporating water
and other fluids. Enough to condense when you rapidly drop the pressure
from around 800 to 300 mb.

JG

Bob Gardner wrote:

Gotta admit that I am working from memory of events many long years ago and
may easily have screwed up the details. With regard to the fog, however,
there has to be moisture from somewhere...simple expansion is not the whole
story. Fog is, after all, a gazillion eensy-teensy droplets.

When the pressure drops, the temperature drops. All that happened was you went
below the dew point in the chamber.

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