O2 Mask On Pilot?

"Steven P. McNicoll" wrote
(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.

The Part 121 requirement for Certificated Aircarriers is more restrictive
than for Part 91 Operators. The FL350 is replaced with FL 250.

Bob Moore

"Bob Moore" wrote in message
21...

The Part 121 requirement for Certificated Aircarriers is more restrictive
than for Part 91 Operators. The FL350 is replaced with FL 250.


But still not applicable to the Greek 737 that went down yesterday, although
a similar requirement may have existed for them.

On Mon, 15 Aug 2005 23:37:07 GMT, "Steven P. McNicoll"
wrote:

"Bob Moore" wrote in message
. 121...

The Part 121 requirement for Certificated Aircarriers is more restrictive
than for Part 91 Operators. The FL350 is replaced with FL 250.

But still not applicable to the Greek 737 that went down yesterday, although
a similar requirement may have existed for them.

What would have been the effect if the O2 bottle for the cockpit had
been inadvertently filled with breathing air rather than O2? I seem
to remember that this was discovered to have happened somewhere in the
US in the last few months? I would think that a casual test would
have found it normal, but that the PPO2 would have been substantially
too low even with a pressurized mask?

GeorgeB wrote:

What would have been the effect if the O2 bottle for the cockpit had
been inadvertently filled with breathing air rather than O2?

They would have tested the system before the flight and found it
working. They would have put on their mask in flight and thought it
worked, slowly fading away without recognizing it. You may or may not
recognize hypoxia when you suspect it and really watch your body, you
definitely don't recognize it when you're unwary.

Stefan

"Stefan" wrote in message
...
GeorgeB wrote:

What would have been the effect if the O2 bottle for the cockpit had
been inadvertently filled with breathing air rather than O2?

They would have tested the system before the flight and found it working.
They would have put on their mask in flight and thought it worked, slowly
fading away without recognizing it. You may or may not recognize hypoxia
when you suspect it and really watch your body, you definitely don't
recognize it when you're unwary.


The question was what happens when breathing air from the mask rather than
O2 and the answer is nothing at all at a cabin pressure of 10K feet.

fred wrote:

The question was what happens when breathing air from the mask rather than
O2 and the answer is nothing at all at a cabin pressure of 10K feet.

Got me :-). On the other hand, if the bottels were filled with say N2
instead of O2, they would still have faded away even at 10 kft. Further
speculations?

Stefan

"Stefan" wrote in message
...
fred wrote:

The question was what happens when breathing air from the mask rather
than O2 and the answer is nothing at all at a cabin pressure of 10K feet.

Got me :-). On the other hand, if the bottels were filled with say N2
instead of O2, they would still have faded away even at 10 kft. Further
speculations?

Yes and pure N2 is faster than air at 35,000.

fred wrote:

The question was what happens when breathing air from the mask rather than
O2 and the answer is nothing at all at a cabin pressure of 10K feet.

But the question was asked about pilots that were at 35,000'. I believe that
George B. is correct that the partial pressure would be too low and the pilots
would pass out.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

"GeorgeB" wrote in message
...

What would have been the effect if the O2 bottle for the cockpit had
been inadvertently filled with breathing air rather than O2?


From what would the oxygen system be serviced in your scenario? A
compressor?

On Thu, 18 Aug 2005 18:50:06 GMT, "Steven P. McNicoll"
wrote:


"GeorgeB" wrote in message
.. .

What would have been the effect if the O2 bottle for the cockpit had
been inadvertently filled with breathing air rather than O2?


From what would the oxygen system be serviced in your scenario? A
compressor?

I've far more experience with industrial compressed gasses than with
aircraft oxygen, and see much more "compressed breathing air" than
BREATHING compressed O2. (Oxygen for oxyacetelyne is to different
standards, but I think it is just as good; several college buddies
would spend some time breathing it after having too much to drink the
night before. Ah, the REAL hangover cure.

Firefighters and scuba divers use it in large quantiies. Bottles are
common with gas suppliers. What I don't know is how the fittings
compare.

Nor do I know how a plane's bottles are filled; via compressor from
low pressure sources, high pressure via cascade bottles, or ???

I do know that the fittings need to be clean of oxydizable materials;
storoes of a little oil on gauge threads, if true, keep one careful.