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good afternoon folks this is your
captain speaking
thanks again for flying with us on psi
Airlines we've got a bit of a delay here
just waiting for the green light to land
from ATC
well we're all twiddling our thumbs how
about I tell you about the two kinds of
cabin pressure okay you're all still
staring at your phones aren't you here
how's this do you like being able to
breathe during the flight there we go
got your attention yes the only reason
you can breathe on a plane in flight is
because we the crew keep it pressurized
but what exactly does pressurizing the
cabin mean when you're mid-flight on a
jet here about 30,000 feet in the air at
an altitude higher than the mighty
Everest itself the air is hard to
breathe why because it's thinner meaning
the molecules are spread further apart
and those include gas molecules like
oxygen yep the very stuff you need to
breathe think of your lungs as balloons
at sea level where the air is nice and
thick you can take in a big full breath
and fill those balloons all the way up
at a high altitude those balloons
wouldn't expand much at all even if you
took the biggest breath you can I know
your next question why don't our craft
just fly lower well small planes and
helicopters don't fly as high and they
don't require pressurization but they
also don't fly as fast or over such long
distances those big airliners that cross
the ocean and save you time on trips
they like to fly high much higher than
the 10,000 feet threshold higher than
that and cabin pressurization becomes a
must that way they burn less fuel
since the aircraft isn't fighting as
much air resistance plus
there isn't as much turbulence and bad
weather up there so it's safer now how
exactly do we pressurize the cabin it's
like pumping of a tire air is sent into
the cabin during your whole flight but
it isn't the stuff that's surrounding
the outside of the plane that's how they
used to do it the air comes from the
engines don't worry
it's not exhaust fumes it's clean air
siphoned from the part of the engine
before it even touches exhaust since the
cabin is sealed the air pressure inside
goes up it's all in delicate balance you
can't pump in too much air or else you
might blow the windows out but too
little would mean everybody on board
passing out and one more thing we don't
pump the same amount of pressure you
feel at sea level such a huge difference
inside and outside the plane could pop
the fuselage apart the pressure in the
cabin and 30,000 feet is what it feels
like at 7,000 feet how is this air
breathable well believe it or not this
air that comes from the engines is
probably cleaner than what's in your
house even though it's clean to start
with it goes through a filtration system
before it even touches your lungs it's
scorching hot at first too so it gets
chilled down yep it's that very same air
that has you shivering throughout the
flight finally most of the water is
removed before it's sent to the cabin
which is why the air on airplanes is so
dry after it's pumped through the cabin
it leaves throughout flow valves this
air cycle is continuously going so that
you passengers and we crew have
brand-new fresh air to breathe every two
to three minutes who all controls this
us the pilots of course okay we do have
some help from a computer that can
automatically adjust the air pressure
inside the cabin fine a lot of help
hence the hall automatic thing but I do
have controls on my instrument panel if
I need to override the
or control the cabin pressure manually
if the system fails what would happen if
the cabin wasn't pressurized well as I
mentioned breathing would be a real
chore you try to take air into your
lungs but it just wouldn't have enough
oxygen you often associate this gas with
your lungs but it's only part of the
equation from there your blood moves
this oxygen to all of your internal
organs muscles and cells and most
importantly your brain needs it to keep
you conscious if the body isn't getting
enough oxygen it could lead to a
condition called hypoxia but it's not
like you just pass out immediately there
are warning signs and what are the
symptoms of hypoxia you ask well it's
not fun that's for sure you'd feel
nauseous dizzy short of breath sweaty
and disoriented another sign you can
look for in yourself or fellow
passengers is constant yawning although
I'd recommend looking for other red
flags if you see someone yawning they
might just be bored and tired by the way
the cabin is kept so-called
hardly to keep people from passing out
so next time you feel a rant coming on
about the temperature try to understand
that the crew and I have your best
interest at heart okay you over there
hitting the flight attendant call button
can we kindly knock that off until I'm
done with my spiel here I'll make sure
you get some extra pretzels and a diet
cola thanks pal all right what if the
air pressure does get too low inside the
plane this would only happen in an
emergency like if the air pressure drops
so fast that the computer couldn't fix
it or if the computer wasn't working for
some reason but this situation is
exactly what those oxygen masks are for
the flight attendant just talked about
it were you paying attention if the
cabin loses pressure the oxygen mask
will drop from the ceiling this is when
you should put the mask over your nose
and mouth tighten the strap and breathe
normally as the preflight safety
demonstration normally goes
how does air pressure work during
takeoff well before I get this plane up
in the air those out flow valves I
mentioned earlier are open once everyone
has boarded I said a cruise altitude
with an air pressure controller as the
plane is climbing during takeoff those
out flow valves automatically close and
the cabin starts filling with air by the
way this is why your ears pop because of
the pressure difference grab a piece of
gum or candy
it'll help think of setting the cruise
control in your car you don't feel
yourself going faster because the
increase in speed is slow and steady
it's the same on a plane it takes around
20 minutes to reach 30,000 feet so the
air pressure rises steadily with you all
right what about landing so all that
goes the other way around
when it's time to start descending we
pilots set the cruise altitude to the
altitude of the airport we're landing at
the cabin pressure goes down at a safe
pace so that no one gets hypoxia when
you pull into the airport and the plane
is completely stopped those on flow
valves open again and all the air
pressure is let out pretty incredible
how planes are designed to take care of
all of this automatically a but that
begs the question how did early flights
deal with pressurization the problem was
that pilots and passengers back then
we're experiencing hypoxia they just had
a little trouble coming up with a
solution people tried some bizarre
methods like wearing masts with a rubber
breathing tube that went to an oxygen
tank needless to say no one was a fan so
the research on pressurization began we
saw the first pressurizing systems as
early as the 1930s windows were made
smaller and reinforced and the cabin was
sealed like a container the system
needed tweaking but they eventually got
there so what's the next big thing in
aviation technology
we have electric cars and trains
airplanes will soon be electric - this
is exciting because it comes with some
major perks hypersonic flight which
would mean arriving at your vacation
spot even faster scientists are also
working on biofuels so planes will be
more eco-friendly and give off fewer
greenhouse gases and guess what
flying taxis aren't too far off and they
won't need pilots Oh does that mean I'll
be out of a job oh I almost forgot
remember I said there were two kinds of
cabin pressure yeah the second kind is
the pressure your pilots feel up here on
the flight deck to get you nice people
out of the cabin so we can load up some
more paying passengers and fly the other
way on that note it looks like it's time
to hit the runway
well maybe not hit the runway so much as
land this big metal pressurized -
traveling over 100 miles an hour as
softly as a feather welcome to your
destination and thanks for flying with
us today on psi hey if you learned
something no today then give this video
a Roger that and share it with a friend
here are some other appropriate videos I
think you'll enjoy just click to the
port or starboard and as a reminder stay
on the bright side of life and don't
play on the runway either you'll get run
over
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