The biweekly inspection includes all the
tasks of the weekly inspection and the following
1. Inspect the pump drive belt for proper
tension, pulley alignment, excessive belt wear, and
tightness of pulley setscrews.
2. Perform the orifice calibration check in
accordance with AVAIR 13-1-6.4.
3. Perform the flowmeter intercomparison
test in accordance with NAVAIR 13-1-6.4.
The monthly inspection includes all the tasks
of the biweekly inspection and the following ad-
1. Inspect the N2 and air inlet connectors for
dirt, foreign matter, corrosion, stripped threads,
and badly scared surfaces.
2. Inspect the gaskets at bulkhead fittings and
vacuum pump filters for deterioration and proper
fits and alignments.
3. Inspect the copper tubing for corrosion and
tightness of soldered joints.
4. Inspect the altitude chamber for clean-
liness, proper fit and alignment of gaskets,
excessive scratches on chamber door, leaks or
corrosion at pipe fittings, and wear of the door
5. Inspect all tubing and piping for tightness
and proper alignment.
6. Inspect all electrical plugs, connectors, and
wiring for physical damage, bent pins, loose
connections, and security of cables.
7. Inspect all control valves for cleanliness and
tightness of mounting nuts and knobs.
The intercomparison test compares the input
and output Vol-O-Flo elements to determine if the
flowmeters need calibration. It is performed more
often than the orifice calibration test as it is
quicker and easier to perform.
The orifice calibration check accurately
determines whether the output Vol-O-Flo is within
When a test stand fails the intercomparison
test, an orifice calibration check is performed.
Failure of the intercomparison test and orifice
calibration check requires the removal and clean-
ing of the input and output Vol-O-Flo elements.
NOTE: Prior to performing these calibra-
tion checks, you should ensure that there
is no test stand leakage.
After cleaning, drying, and reinstallation of
the Vol-O-Flo elements, both the intercomparison
test and the orifice calibration check must be
repeated. Failure of the above tests after clean-
ing will require the test stand be calibrated with
a master calibrator, used by the metrology calibra-
VOL-O-FLO ELEMENT CLEANING
To clean the Vol-O-Flo element, proceed as
1. Disconnect the tubes from Vol-O-Flo
NOTE: Prior to removal of the element,
mark the direction of the flow to ensure
2. Disconnect the element from the plumbing
system by removing the hose and hose clamps at
the ends of the element.
3. Mix a cleaning solution of 4 percent liquid
detergent and water. (Mix 6 ounces of detergent
with 1 gallon of water.)
4. Flush the element in reverse from the
direction in which the air normally flows.
5. After the element has been well flushed, the
detergent is rinsed out immediately with clean
6. Install the element in the test stand,
and create a flow through the element for
approximately 1 hour to ensure that it is
7. After the element is dried, the test stand
8. Perform an intercomparison test and
orifice calibration check in accordance with the
LIQUID OXYGEN CONVERTER
Liquid oxygen converters are another group
of items that you, as a PR, are required to test
and repair. There are two test stands designed to
test the oxygen converters. The operation,
maintenance, and parts are, with a few minor