CONVERTER CHARGE

Upon completing the bench test, the converter is emptied of LOX, purged with nitrogen, and pressurized with gaseous oxygen at 25 to 30 psig.

This prevents moisture from entering the converter during shipment/storage. Locate the indicated psig for the actual pressures of 25 to 30 psig on correction card number 2. Enter indicated psig in spaces provided on the performance test sheet.

MAINTENANCE

This section contains the procedural steps for inspecting, testing, troubleshooting, disassembly, cleaning, repair, assembly and adjusting of the GCU-24/A liquid oxygen converter assembly (P/N 10C-0016-10).

Procedural steps outlined in this section are listed under the inspection cycle in which they are required, and in the sequence in which they normally occur.

ACCEPTANCE/TURNAROUND/ DAILY/PREFLIGHT/POSTFLIGHT AND TRANSFER INSPECTIONS

The acceptance/turnaround/daily/preflight/ postflight and transfer inspections consist of a visual inspection followed by a functional test. These inspections and tests are performed along with the aircraft inspection requirements for the aircraft in which the converter is installed. In making the following checks, if you discover any defects, refer to table 12-17 for troubleshooting assistance.

H₂O

Table 12-17.-Troubleshooting (Acceptance/Turnaround/Daily/Preflight/Postflight and Transfer Inspections)

VISUAL INSPECTION

Visually inspect the converter assembly and surrounding area for the following:

1. Freedom from dirt and hydrocarbons.

2. Correct installation and positioning of all components, safety wire, and Glyptal dots.

3. Legibility of all markings.

4. Cracks, dents or other damage to and electrical connections.

5. Corrosion on converter assembly and tubing, valves and electrical surrounding areas.

6. Obstructions in aircraft overboard vent line.

7. Security of supply, quick-disconnects.

8. Excessive frosting of converter assembly.

9. Ensure date on converter bench test decal is current (within last 231 days). functional test should also be performed by the

FUNCTIONAL TEST

In addition to the scheduled test, the AME whenever a component of the aircraft oxygen system is removed/replaced. As a PR you may be called upon to perform this test. To functionally test the converter assembly and aircraft oxygen system, proceed as follows:

1. Ensure all circuit breakers associated with the LOX quantity indicating system are set. External electrical power must be applied to the aircraft to perform steps 2 and 3 below.

2. Depress oxygen test switch. Check the quantity gauge and low warning light for proper operation. Refer to the applicable aircraft Handbook of Maintenance Instructions (HMI) to determine at what quantity (indicated on quantity gauge) that the low warning light should illuminate.

3. Release test switch. Ensure gauge pointer returns to position registered on gauge before depressing. When test is completed, disconnect electrical power for aircraft.

4. Ensure oxygen shutoff valve is in the OFF position.

5. Attach an oxygen mask, regulator and regulator-to-seat kit hose assembly to oxygen supply connection in aircraft.

6. Turn oxygen shutoff valve to the ON position. There should be a flow of oxygen through the mask.

7. Place the mask against your face and breathe. There should be a slight resistance during exhalation. This resistance is due to the positive pressure feature of the regulator.

8. Upon completing the functional test, turn the oxygen shutoff valve to OFF. Disconnect the regulator-to-seat kit hose from the aircraft supply connection.

If discrepancies are found or suspected, notify maintenance control.

Components of the aircraft oxygen system that do not pass inspection and cannot be repaired in the aircraft are removed and replaced by ready for issue (RFI) components.