PERIODIC INSPECTIONS

Periodic inspections consist of daily, weekly, biweekly, and monthly inspections. Perform these inspections at the prescribed intervals using the procedures described in the following text.

Daily Inspection

Perform the daily inspection as follows:

1. Check the vacuum pump lubricant for the proper level (run the pump for 2 minutes and recheck for proper level).

2. Inspect the gauges and manometers for cleanliness, fogged or broken glass, and zero or normal indications.

3. Inspect the altitude chamber door for cleanliness, chips, scratches or cracks. Check the gaskets for excessive wear or deterioration.

4. Inspect the connections and adapters for cleanliness and distortion.

5. Check the identification plates for cleanliness, legibility, and security of attachments.

Weekly Inspection

The weekly inspection includes all the tasks of the daily inspection and the following additional tasks:

1. Inspect the polyethylene tubing, fittings, connections, and rubber couplings for the correct fit, dirt or excessive dust, pin holes, radical bends or kinks, surface abrasions and heat blisters.

2. Inspect the gauges, manometers, and flowmeters for the correct calibration decals, proper fluid level, and cleanliness of manometer and flowmeter tubes.

3. Perform the pressure leakage tests in accordance with NAVAIR 13-1-6.4.

Biweekly Inspection

The biweekly inspection includes all the tasks of the weekly inspection and the following additional tasks:

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.

Monthly Inspection

The monthly inspection includes all the tasks of the biweekly inspection and the following additional tasks:

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 cleanliness, proper fit and alignment of gaskets, excessive scratches on chamber door, leaks or corrosion at pipe fittings, and wear of the door gasket.

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.

VOL-O-FLO CALIBRATION

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 calibration tolerances.

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 cleaning of the input and output Vol-O-Flo elements.

NOTE: Prior to performing these calibration 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 cleaning will require the test stand be calibrated with a master calibrator, used by the metrology calibration team.

VOL-O-FLO ELEMENT CLEANING

To clean the Vol-O-Flo element, proceed as follows:

1. Disconnect the tubes from Vol-O-Flo manometers.

NOTE: Prior to removal of the element, mark the direction of the flow to ensure proper reinstallation.

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 water.

6. Install the element in the test stand, and create a flow through the element for approximately 1 hour to ensure that it is completely dry.

7. After the element is dried, the test stand is leak-tested.

8. Perform an intercomparison test and orifice calibration check in accordance with the NAVAIR 13-1-6.4.