by this volume of oxygen acting on the demand valve
6. The addition of ambient air to oxygen is
lever assembly to the extent that the positive pressure is
controlled by the manual diluter control lever (13) and
built up at the pressure outlet as the altitude increases.
by the diluter aneroid assembly (14), which
automatically produces a 100-percent oxygen
10. Additional safety is obtained through the
concentration at altitudes above 32,000 feet.
inclusion of the second-stage relief valve assembly (23)
in the regulator.
7. The aneroid check valve assembly (15)
prevents a flow of oxygen out through the inlet ports.
TURNAROUND/PREFLIGHT/POSTFLIGHT/
TRANSFER INSPECTIONS.--These inspections
8. The emergency pressure control lever (16)
are visual inspections performed in conjunction with
applies force to the emergency pressure control test
the inspection requirements for the aircraft in which the
spring (17), which mechanically loads the emergency
regulators are installed. Refer to table 7-2 for assistance
pressure diaphragm through the control lever and
in troubleshooting.
center assembly (18). Mechanical loading of the
emergency pressure diaphragm provides positive
Visually inspect the following:
pressure at the regulator outlet.
Electrical performance of the panel light
9. Both automatic safety pressure and pressure
Legibility of all marking
breathing at altitudes above 30,000 feet are provided
Plastic lighting plate for cracks and dis-
through pneumatic actuation of the aneroid assembly
coloration
(19). This function begins near 27,000 feet altitude. The
Low or improper reading on regulator pressure
force exerted on the diaphragm assembly (20) by the
gauge
aneroid assembly actuates the pressure breather valve
Emergency pressure control lever in NORMAL
assembly (21), and the oxygen flows to the diaphragm
and the plate assembly (22), which is pressure loaded
position
Table 7-2.--Gaseous Oxygen System Troubleshooting
TROUBLE
PROBABLE CAUSE
REMEDY
Oxygen cylinder pressure Defective gauge
Replace regulator
gauge fails to indicate
Blocked or leaking supply line
Replace or clean supply line to regulator
proper pressure
Low cylinder pressure
Refill
Defective manifold inlet assembly
Replace regulator
Oxygen not available at Regulator controls improperly positioned
Correct position of controls
mask with proper pressure
Hose to mask is kinked
Straighten hose and reposition outlet
source to regulator and
other than emergency setting Regulator not functioning properly
Replace regulator
on regulator
Kink or other malfunction between hose Replace or readjust equipment as necessary
Oxygen not available at
and mask
mask with proper pressure
source to regulator and
Faulty linkage from emergency pressure Replace regulator
regulator controls set at
control lever
EMERGENCY
Oxygen available at mask Defective blinker assembly
Replace regulator
but flow is not indicated
Gauge pressure drops when
Loose or leaking connections
Tighten or replace connections as necessary
regulator is not in use
Defective manifold inlet assembly
Replace regulator
Panel light fails to light
Burned out lamp
Replace regulator
Faulty light assembly
Replace lamp
Faulty electrical hookup to power source
Repair electrical hookup
7-17
