C560 captain reported that the crew oxygen masks did not pass the test.

Attributes
ACN	1545609
Time
Date	201805
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	Citation V/Ultra/Encore (C560)
Operating Under FAR Part	Part 91
Flight Phase	Parked
Component
Aircraft Component	Oxygen System/Crew
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural FAR Deviation - Procedural Maintenance

Narrative:

During pre-flight; captain's oxygen mask passed test. Co-pilot's mask did not pass test. I then tested the captain's mask again and it failed; no oxygen pressure to mask. Maintenance was notified and they discovered the oxygen bottle control valve; which is under a secure panel in the tail; was almost completely shut off. This configuration allowed just enough oxygen pressure to the mask for it to pass a quick test. The bottle valve was not safety wired in the open position either. If we would've needed oxygen during flight; we wouldn't have received any in the cockpit or cabin.I would suggest the company notify all crews to actually remove the mask; make sure it inflates; has pressure and works properly for at least 30 seconds.

Original NASA ASRS Text

Title: C560 Captain reported that the crew oxygen masks did not pass the test.

Narrative: During pre-flight; Captain's oxygen mask passed test. Co-pilot's mask did not pass test. I then tested the Captain's mask again and it failed; no oxygen pressure to mask. Maintenance was notified and they discovered the oxygen bottle control valve; which is under a secure panel in the tail; was almost completely shut off. This configuration allowed just enough oxygen pressure to the mask for it to pass a quick test. The bottle valve was not safety wired in the open position either. If we would've needed oxygen during flight; we wouldn't have received any in the cockpit or cabin.I would suggest the company notify all crews to actually remove the mask; make sure it inflates; has pressure and works properly for at least 30 seconds.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.