FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 9. Aircraft Systems and Components | 3. Emergency Equipment | 9-50. Functional Testing After Repair
9/27/01
AC 43.13-1B CHG 1
9-50. FUNCTIONAL TESTING AFTER
REPAIR. Following repair, and before in-
spection plates, cover plates, or upholstering
are replaced, test the entire system.
a. Open the cylinder valve slowly and
observe the pressure gauge on a high-pressure
system. A pressure of approximately 1,800 psi
(at 70 °F) should be indicated on the gauge.
(Cylinder pressure will vary considerably with
radical temperature changes.)
(1) Check the system by installing one
of the mask hose fittings (minus the mask) in
each of the cabin wall outlets to determine
whether there is a flow. If a demand mask is
used, check by breathing through the mask
and, if appropriate, clean the mask according
to paragraph 9-49d.
(2) Check the complete system for leaks
in accordance with the procedure outlined in
paragraph 9-49b(2)(d).
(3) If leaks are found, close the cylinder
valve and open an outlet to reduce the pressure
in the system to zero.
b. The following checks may be made for
a pressure drop check of the system.
(1) Open the cylinder valve and pres-
surize the system. Observe the pressure gauge
(a pressure of approximately 1,800 psi at 70 °F
should be indicated). For the light weight
ICC 3HT 1850 cylinders, pressurize the system
to approximately 1,850 psi at 70 °F.
(2) Close the cylinder valve and wait
approximately 5 minutes for temperatures to
stabilize.
(3) Record the pressure gauge reading
and temperature and after 1 hour, record the
pressure gauge reading and temperature again.
(4) A maximum pressure drop of
100 psi is permissible.
NOTE: Conduct the above tests in an
area where changes of temperature
will be less than 10 °F. If a leak oc-
curs during the 1-hour period, suit-
able corrections would be required, or
reconduct the test under conditions of
unvarying temperatures.
9-51. SERVICE OXYGEN CYLINDERS.
REQUIREMENTS (Ref 49 CFR 173.34 e,
16). Standard-weight cylinders must be hydro-
static tested at the end of each 5-year period
(10 years if it meets the requirements in 49
CFR 173.34 e, 16). This is a Department of
Transportation (DOT) requirement. These-
cylinders carry an ICC or DOT 3AA 1800
classification and are suitable for the use in-
tended.
Lightweight cylinders must be hydrostatic
tested every 3 years, and must be retired from
service after 24 years or 4,380 pressurizations,
whichever occurs first. These cylinders carry
an ICC or DOT 3 HT 1850 classification and
must be stamped with the approval after being
inspected. (Ref. 49 CFR 173.34 e, 15).
CAUTION: Use only aviation
breathing oxygen when having the
oxygen bottle charged.
a. Charging High-Pressure Oxygen
Cylinders. The following are recommended
procedures for charging high-pressure oxygen
cylinders from a manifold system, either per-
manently-installed or trailer-mounted.
CAUTION: Never attempt to charge
a low-pressure cylinder directly from
a high-pressure manifold system or
cylinder.
Par 9-49
Page 9-41