Installation diagrams provided in either the MIM or
Malfunctions may become apparent during
the illustrated parts breakdown (IPB) will assist you in
inspections, testing, or actual use of the oxygen system.
locating the particular component in the aircraft.
The remedies for some malfunctions will be quite
obvious, while in other cases it may require ex-
The MIMs provide a variety of troubleshooting
tensive time and effort to pinpoint the actual cause.
charts, which are intended to aid you in discovering the
The effectiveness of corrective action will be
cause of malfunction and its remedy. Table 7-1
dependent on an accurate diagnosis of the mal-
illustrates one type of chart. The discrepancy is listed in
function.
the first column with the probable cause in the second
and the remedy in the third. The list of probable causes
Troubleshooting of the gaseous oxygen system, as
is arranged in the order of probability of occurrence.
with the other systems, is the process of locating a
malfunctioning component or unit in a system or
Q7-8. The pressure in gaseous oxygen supply
mechanism. To troubleshoot intelligently, you must be
cylinders should not be allowed to fall below
familiar with the system and know the function of each
what level?
component within the system. You can study the
Q7-9. What is the preferred compound for use in
schematic diagrams of the system provided in the MIM
oxygen system cleaning?
to gain a mental picture of the location of each
component in relation to other components. By
Q7-10.
True or False. Oxygen systems can be used as
learning to interpret these diagrams, you can save
a substitute for compressed air.
time in isolating malfunctioning components. The
Q7-11.
What component is used to direct the oxygen
schematic diagram does not indicate the location of
to the user's respiratory system?
components in the aircraft; however, it will provide the
means to trace the oxygen flow from the cylinder
Q7-12.
What are the two most common cylinder
through each component to the mask.
sizes?
Table 7-1.--Gaseous Oxygen System Troubleshooting
Discrepancy
Probable Cause
Remedy
Excessive leakage of system pressure.
Filler valve leaking.
Replace filler valve.
Leak in lines.
Check tubing, fittings, and connections and
repair or replace as necessary.
Flexible hose leaking.
Replace hose.
Regulator not shut off.
Shut off regulator.
Crewmember receives insufficient oxygen
Improperly functioning regulator.
Replace regulator.
at high altitude.
Ill-fitting mask.
Refit or replace mask.
Mask flapper valve not operating
Check mask exhaust valve.
properly.
Flexible tubing to mask crushed
Replace tubing as necessary.
or kinked.
No pressure reading at the regulator
Defective regulator.
Replace regulator.
Oxygen supply turned off.
Turn on cylinder hand valve if so equipped.
System not charged.
Replenish oxygen supply.
Regulator pressure gauge indications are
Gauge defective.
Replace gauge.
incorrect.
Regulator flow indicator not functioning.
Indicator defective.
Replace regulator.
7-9
