CHAPTER 12
Oxygen
craft. They
OXYGEN-RELATED COMPONENTS
Learning Objective: Upon completion of this chapter, you will be able to
identify, maintain, and perform maintenance on oxygen regulators and
liquid oxygen converters.
regulators are used in all naval air-
supply the aircrew member with the
necessary oxygen to perform all flying duties
under all kinds of conditions. As a PR, you will
maintain, service, and test oxygen regulators and
liquid oxygen converters. This chapter will give
you a basic idea of how a miniature oxygen
regulator functions, as well as a panel-mounted
regulator and a liquid oxygen converter. It will
also cover some of the maintenance that you must
perform. The miniature regulator shown in figure
12-1 is a model 29267-A1, type CRU-79/P, and
this model is manufactured by Bendix Aviation
Corporation. Other models are manufactured
by Clifton Precision, Robert Shaw Controls
Company and ARO Corporation, but all are type
CRU-79/P. They are designed to regulate
100-percent oxygen to the aircrew member
during flight. Table 12-1 contains the leading
particulars for the regulator.
The miniature regulator reduces and regulates
supply oxygen pressure to provide an adequate
amount for breathing under a variety of condi-
tions. It has a safety-pressure feature that
automatically maintains a positive pressure in the
aircrew members mask of 0.50 to 2.5 inches of
water above the surrounding air pressure.
(Inches of water is a means of measuring the
comparatively low pressure used in testing oxygen
regulators.) This positive pressure is maintained
at all altitudes up to and including 34,000 feet.
Above that altitude, the pressure-breathing
feature maintains a positive pressure in the
mask of up to 18.0 inches of water at altitudes
between 34,000 and 50,000 feet, with the positive
pressure increasing in proportion to the altitude.
Miniature regulators can be used routinely up to
approximately 43,000 feet. However, due to
human limitations, miniature regulators should
Figure 12-1.-Miniature oxygen breathing regulator model
29267-A1.
Table 12-1.-Leading Particulars for Miniature Oxygen
Breathing-Regulator Type CR79/P
not be used above 43,000 feet except for very short
periods.
Miniature regulators are designed for use with
the MBU-14 series oxygen mask as part of the
oxygen system in all aircraft requiring 100-percent
oxygen chest-mounted regulators. Refer to the
NAVAIR 13-1-6.7 manual for personal configura-
tions of the MBU-14 series oxygen mask.
12-1
