OXYGEN
DURATION
CALCULATION.
The Oxygen Duration
Chart
(figure 7-2) should be used in
determin-
ing the usable duration (in hours)
of
the oxygen supply
in
your
airplane.
The following
procedure
outlines the method
of
finding the duration from
the
chart.
(1)
Note the available oxygen
pressure
shown
on
the
pressure
gage.
(2)
Locate this
pressure
on
the
scale
on
the
left
side
of
the
chart,
then
go
across
the
chart horizontally
to the
right
until
you
intersect
the line
representing
the number
of
persons
making the flight.
After
intersecting
the line, drop
down
vertically
to the bottom
of
the
chart
and
read
the
duration
in
hours
given
on
the
scale.
(3)
As an example
of
the above
procedure,
1400
psi
of
pressure
will
safely
sustain
the pilot only
for nearly
6
hours and
15
minutes.
The
same
pressure
will
sustain
the pilot and
three passengers
for approx-
imately
2
hours and
30
minutes.
NOTE
The Oxygen Duration
Chart
is
based
on a
standard
con-
figuration
oxygen
system
having
one
orange
color-coded
hose
assembly
for the
pilot
and
green color-coded hoses
for
the
passengers.
If
orange
color-coded hoses are
provided
for
pilot and
passengers, it
will be
necessary
to compute new
oxygen
duration
figures
due to
the
greater
consumption
of
oxygen with
these hoses.
This is
accom-
plished
by
computing the
total
duration available
to
the
pilot
only (from "PILOT
ONLY"
line
on
chart),
then
di-
viding this
duration
by the number
of
persons
(pilot
and
passengers)
using oxygen.
OXYGEN
SYSTEM SERVICING.
The oxygen
cylinder,
when
fully charged, contains approximately
48
cubic
feet
of
oxygen, under a
pressure
of 1800
psi
at 70°F.
Filling
pressures
will
vary,
however,
due
to the ambient
temperature
in the
filling
area,
and
because
of
the
temperature
rise
resulting from com-
pression
of
the oxygen. Because
of
this, merely
filling to
1800
psi
will
not
result
in a
properly
filled cylinder.
Fill
to the
pressures
indicated
in the
table
on
the following page
for
ambient
temperature.
7-9
Summary of Contents for 182 1973
Page 3: ......
