oxygen test

[SCARTER 0]

This is how you do an oxygen test..press the left button and hold then go to the radio screen and turn on the speaker icon what you are doing is to see is how the mic is working inside of the oxygen mask..what i learned from a B747 400  UPS Captain

[SCARTER 0]

STEVE CARTER

[Copper. 78]

Hello Steve 

Yes, that’s right. The procedure is contained within a manual called Flight Crew Operations Manual, in the Amplified Procedures for Captain and First Officer. If the other positions are used (1st and 2nd observers), they must also be checked. Although, the 1st and 2nd obs controls don’t work on PMDG 747.

Also, that is part of the reason why the “OXYGEN................TESTED, 100%” item in the Normal Checklist (PREFLIGHT) exists. Note that some airlines check the microphone, some airlines don’t.

The other reason is, maintenance personnel forget to open the oxygen bottles. This is noticeable by a dip in the oxygen pressure followed by either a slow rise back to starting pressure, or, no recovery of the pressure.

A slow recovery - for example the pressure drops from 1850psi to 1500psi, then slowly increases back to approximately 1800-1850psi after the “10second test” - indicates to crew the oxygen bottles aren’t fully open.

No recovery - for example the pressure drops from 1850psi to 1500psi or even lower, but does not subsequently increase - indicates the bottle/s are closed.

Oxygen pressure is displayed on the EICAS Status Synoptic page and should be monitored for correct behaviour whilst running the test.