Md-83 first officer discovers his oxygen mask exhale diaphragm is stuck after donning the mask in cr...

Narrative:

While in cruise I put on my O2 mask as the captain was leaving the flight deck. I couldn't exhale from the mask as the diaphragm appeared to be stuck. I held the mask tightly to my face and blew very hard which 'broke open' the diaphragm. I then decided to switch to emergency on the O2 panel but was unable to because there was some type of locking pin that appears non compliant; preventing its removal without a tool as it was jammed against the panel. Had I actually need emergency oxygen; this could have become a very serious issue. This pin was obviously not the pin that is supposed to be installed. It concerns me that it is our culture here to 'just get it done' and there was no consideration of whether or not a pilot would actually be able to select emergency O2 in an emergency. Standards should be followed in actions and the type of parts we use. I have sent a picture of the panel to [the chief pilot].

Original NASA ASRS Text

Title: MD-83 First Officer discovers his oxygen mask exhale diaphragm is stuck after donning the mask in cruise. A hard blow breaks it loose but it is then discovered that the emergency oxygen switch is pinned in the off position and the pin cannot be removed.

Narrative: While in cruise I put on my O2 mask as the Captain was leaving the flight deck. I couldn't exhale from the mask as the diaphragm appeared to be stuck. I held the mask tightly to my face and blew very hard which 'broke open' the diaphragm. I then decided to switch to emergency on the O2 panel but was unable to because there was some type of locking pin that appears non compliant; preventing its removal without a tool as it was jammed against the panel. Had I actually need emergency oxygen; this could have become a very serious issue. This pin was obviously not the pin that is supposed to be installed. It concerns me that it is our culture here to 'just get it done' and there was no consideration of whether or not a pilot would actually be able to select emergency O2 in an emergency. Standards should be followed in actions and the type of parts we use. I have sent a picture of the panel to [the Chief Pilot].

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.

Attributes
ACN	1148502
Time
Date	201402
Aircraft 1
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Oxygen System/Crew
Person 1
Function	First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Deviation - Procedural FAR

Md-83 first officer discovers his oxygen mask exhale diaphragm is stuck after donning the mask in cruise. A hard blow breaks it loose but it is then discovered that the emergency oxygen switch is pinned in the off position and the pin cannot be removed.