The importance of using only those replacement
WARNING
parts specified by NAVAIR 19-25D-31 cannot be over
Relieve all system pressure before performing
emphasized. All hose and tube assemblies shall be
maintenance on any part of the oxygen servicing
suitable for oxygen use as specified by NAVAIR
unit.
01-1A-20, Aviation Hose and Tube Manual. Apply
tetrafluoroethylene tape to pipe threads, starting at the
t h i r d t h r e a d t o p r eve n t c o n t a m i n a t i o n , b e f o r e
assembly. Apply antiseize compound to screw threads
Maintenance of the A/U26U-1
and bearing surfaces of nuts and bolts before torquing
them to specification.
NOTE: All maintenance on the A/U26U-1
oxygen servicing unit shall be performed in
SAFETY
accordance with NAVAIR 19-25D-31, Operation and
Intermediate Maintenance Instructions with
Oxygen can be very dangerous. In all of its forms,
Illustrated Parts Breakdown, Oxygen Servicing Unit,
it supports fire and is subject to explosion. As a
A/U26U-1 and NAVAIR 19-600-269-6-2, Periodic
compressed gas, the principal danger is due to the
M a i n t e n a n c e R e q u i re m e n t s M a n u a l , O x y g e n
rocket-like thrust imparted to a cylinder by the sudden
Servicing Unit, A/U26U-1.
and rapid escape of gas. For example, if the valve of a
cylinder pressurized at 2,500 psig were broken off, the
Aviation Support Equipment Technicians perform
cylinder would have an initial thrust of about 2,600
organizational- and intermediate-level maintenance on
pounds of force. The cylinder could attain a velocity of
the oxygen servicing unit. Maintenance includes
50 feet per second in about one-tenth of a second.
loading, charging, and replacing cylinders;
Another potential hazard results from the increase
miscellaneous parts repair and replacement; and
in pressure of a compressed gas with any increase in
inspections. Procedures for testing and
temperature. Cylinders may explode with great
troubleshooting the servicing unit to isolate defective
violence. Safety plugs may blow out if cylinders are
components/parts are outlined in NAVAIR 19-25D-31.
exposed to higher than normal temperatures.
Cylinders must be handled with care. Mechanical
WARNING
or structural damage may result in cylinders that are
Interchanging parts between oxygen servicing
unable to withstand normal use. Serious accidents
equipment and air/nitrogen equipment is a serious
connected with handling, using, and storing of
safety hazard. All components coming in contact
cy l i n d e r s h ave o f t e n b e e n t r a c e d t o a bu s e o r
with oxygen shall be cleaned in accordance with
mishandling.
MIL-C-52211, Class A.
When handling oxygen, you must follow these
precautions:
Always call oxygen by its proper name. Do not
The maintenance actions performed on the oxygen
confuse oxygen with compressed air. NEVER
servicing unit are similar to those performed on the
use oxygen in place of compressed air for any
nitrogen servicing unit, discussed in chapter 9. Some
purpose.
of the components of the systems are very similar and,
In aircraft gaseous oxygen systems, use only
i n s o m e c a s e s , l o o k i d e n t i c a l ; h ow ev e r, t h e
c o m p o n e n t s c a n N OT b e i n t e r c h a n g e d . T h e
oxygen conforming to MIL-0-27210, Type I.
cleanliness standards for oxygen system components
Exercise care that compressed oxygen does not
far exceeds those for nitrogen system components. To
become contaminated in any way with
make it nearly impossible to interchange similar parts
hydrogen, hydrocarbon gases, or oil-based
between oxygen and air/nitrogen equipment, critical
liquids. Oxygen contaminated with any of these
parts for oxygen equipment (valves, regulators, and
substances can explode.
hoses) have left-hand threads. This means that to
NEVER lubricate oxygen valves, regulators,
tighten oxygen hoses, you turn the fitting
counterclockwise--just the opposite of the way you
gauges, or fittings with oil or any substance
tighten air/nitrogen hoses.
except an approved oxygen compatible
10-37
