WARNING Make certain that when working with oxygen, all clothing, tube fittings, and equipment are free of oil, grease, fuel, hydraulic fluid, or any combustible liquid. Fire and/ or explosion may result when even slight traces of combustible material come in contact with oxygen under pressure.

To perform the functional test, proceed as follows:

1. Place supply valve control lever in the ON position.

2. Place the diluter control lever in the NORMAL OXYGEN position.

3. Connect the oxygen hose to the quick disconnect, place the mask to the face, and inhale. Proper regulator operation will be indicated by the flow indicator assembly

Table 4-3.- Troubleshooting (Daily, preflight, special, turnaround, transfer and acceptance inspections)

showing white during inhalation and black during exhalation. While at ground level, the regulator will not normally supply oxygen from the supply system to the mask. Therefore, the emergency pressure control lever must be used to check the oxygen supply function of the regulator at low altitudes. The emergency lever is spring loaded at the NORMAL position, and will return to NORMAL when released. 4. Hold the emergency pressure control lever in the TEST MASK position and observe the flow indicator. Flow indicator should be white. / indicating a flow through the regulator.

Upon completion of the functional test, secure the regulator as follows:

1. Disconnect the mask from the supply hose.

2. Ensure that the emergency pressure control lever returns to the NORMAL position.

3. Place the diluter control lever in the 100% position.

4. Place the supply valve control lever in the OFF position.

discrepancies are found or suspected. maintenance-control should be notified. Regulators that do not pass inspection and cannot be repaired in the aircraft are removed and replaced by RFI regulators. Non-RFI regulators should be forwarded to the nearest maintenance activity having repair capability.