OXYGEN RATIO TEST

Aircrew Survival Equipmentman 2 - Aviation theories and other practices
Page Navigation
271

OXYGEN RATIO TEST.— This test deter- mines the amount of oxygen mixed with ambient air up to 32,000 feet where 100-percent oxygen will be automatically delivered to the user. To perform the oxygen ratio rest, proceed as follows: 1. Ensure that the regulator supply valve control lever is in the ON position, and the diluter control lever is in the NORMAL OXYGEN position. 2. By using the LOW PRESSURE REGULA- TOR, apply 150 psig to the regulator inlet. Slowly open the VACUUM CONTROL valve (B₁) and observe the PRESSURE/SUCTION manometer. If a rapid increase in pressure is indicated, close down on VACUUM CONTROL valve (B₁) until pressure stabilizes. This rapid increase of pressure shown on PRESSURE/SUCTION manometer is caused by too fast a rate of climb in the altitude chamber. Maintain 3.0 inches of H₂O on the OUTPUT manometer with OUTPUT valve while “ascending to altitude.” 3. Using VACUUM CONTROL valve (B₁), ascend to the first test altitude shown on the Performance Test Sheet. 4. Set the output flows specified in the Performance Test Sheet with OUTPUT valve, and stabilize altitude with INPUT valve. 5. Read all readings on the INPUT manome- ter, and record all readings on the Performance Test Sheet. 6. Continue the test for each specified altitude and output flow shown on the Performance Test Sheet. 7. Close OUTPUT valve and INPUT valve. Descend to 27,000 feet using CHAMBER BLEED valve. 8. If oxygen ratio test was satisfactory, proceed to make the safety pressure and pressure breathing test. If indicated input flows are not within limits, an aneroid closure test must be performed. The aneroid closure test is performed only if regulator fails the oxygen ratio test. ANEROID CLOSURE TEST.— The aneroid closure test is preformed only if the regulator fails the oxygen ratio test. To perform the aneroid closure test, proceed as follows: 1. Descend to 25,000 feet by using the CHAMBER BLEED valve. 2. Ensure that the inlet pressure is as specified on the Performance Test Sheet. 3. Setup a flow of 5.0 inches of H₂O on the OUTPUT FLOW manometer with OUTPUT valve. 4. The aneroid closes between 28,000 and 32,000 feet, as indicated by no further advance in altitude on the LOW RANGE altimeter. 5. Close the OUTPUT valve and descend to sea level by using the CHAMBER BLEED valve. 6. If the regulator fails aneroid closure test and/or oxygen ratio test, locate probable cause using troubleshooting chart, table 12-13. SAFETY PRESSURE AND PRESSURE BREATHING TEST.— This test determines if 100-percent oxygen is being delivered to the user through the regulator between 30 and 50,000 feet. Table 12-13.—Troubleshooting (Oxygen Ratio/Aneroid Closure Tests) 12-16

Privacy Statement
Press Release
Contact