Narrative:

I was initially called in response to an first officer's boom microphone problem in which the captain and I operations check and worked normally. He told me that his crew oxygen pressure was down to 700 psi and will not see maintenance today and said it will restrict the flight deck observer position. I elected to change the bottle and called the lead for a new serviced oxygen bottle. I went to fwd cargo bay and removed the old bottle per the maintenance manual for a new one. I received a new light weight bottle and installed per maintenance manual. While installing; I slowly opened the valve until it stopped. I felt that was not enough turns so I attempted to open it further until I felt pain in my wrist. I knew that the new bottle has less turns than the old style; so I assumed bottle was completely opened then I turned a 1/4 turn closed and safety wired with brass wire. Leak checked bottle which was good. I called to my assistant who was on the flight deck to proceed with crew oxygen pressure test. He acknowledged that he and the captain witnessed no observable pressure drop of 100 psi or greater from all 3 stations. My assistant called for my employee number for the logbook signoff in which I gave him my number of XXX. Flight departed to ZZZ where crew change occurred. During preflight of their oxygen; crew noticed a drop from 1600 psi to 1100 psi. Contract maintenance was called and reported that he got seven more turns of the bottle valve. I do not concur with contract maintenance from when my supervisor called and reported this information to me at xa:00 pm. I stated that everything was done per the maintenance manual so I talked to two other supervisors to get more information to see if the valve malfunctioned on the bottle.callback conversation with reporter revealed the following information: the reporter stated the new composite bottle was installed per the maintenance manual and the bottle valve was turned to open using hand force. Later the reporter was advised the bottle valve was able to be turned another seven turns. This new composite oxygen bottle; when being filled; heats up slightly and causes the shutoff valve to stop turning to the open position short of full open. The valve cannot be forced beyond where it stops.

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Original NASA ASRS Text

Title: A B737-700 HAD A CREW OXYGEN BOTTLE REPLACED AND TESTED OK. LATER IN DAY OXYGEN REQUIRED CHKING AND BOTTLE VALVE WAS FOUND NOT FULLY OPENED.

Narrative: I WAS INITIALLY CALLED IN RESPONSE TO AN FO'S BOOM MIC PROBLEM IN WHICH THE CAPT AND I OPS CHK AND WORKED NORMALLY. HE TOLD ME THAT HIS CREW OXYGEN PRESSURE WAS DOWN TO 700 PSI AND WILL NOT SEE MAINT TODAY AND SAID IT WILL RESTRICT THE FLT DECK OBSERVER POSITION. I ELECTED TO CHANGE THE BOTTLE AND CALLED THE LEAD FOR A NEW SERVICED OXYGEN BOTTLE. I WENT TO FWD CARGO BAY AND REMOVED THE OLD BOTTLE PER THE MAINT MANUAL FOR A NEW ONE. I RECEIVED A NEW LIGHT WT BOTTLE AND INSTALLED PER MAINT MANUAL. WHILE INSTALLING; I SLOWLY OPENED THE VALVE UNTIL IT STOPPED. I FELT THAT WAS NOT ENOUGH TURNS SO I ATTEMPTED TO OPEN IT FURTHER UNTIL I FELT PAIN IN MY WRIST. I KNEW THAT THE NEW BOTTLE HAS LESS TURNS THAN THE OLD STYLE; SO I ASSUMED BOTTLE WAS COMPLETELY OPENED THEN I TURNED A 1/4 TURN CLOSED AND SAFETY WIRED WITH BRASS WIRE. LEAK CHKED BOTTLE WHICH WAS GOOD. I CALLED TO MY ASSISTANT WHO WAS ON THE FLT DECK TO PROCEED WITH CREW OXYGEN PRESSURE TEST. HE ACKNOWLEDGED THAT HE AND THE CAPT WITNESSED NO OBSERVABLE PRESSURE DROP OF 100 PSI OR GREATER FROM ALL 3 STATIONS. MY ASSISTANT CALLED FOR MY EMPLOYEE NUMBER FOR THE LOGBOOK SIGNOFF IN WHICH I GAVE HIM MY NUMBER OF XXX. FLT DEPARTED TO ZZZ WHERE CREW CHANGE OCCURRED. DURING PREFLT OF THEIR OXYGEN; CREW NOTICED A DROP FROM 1600 PSI TO 1100 PSI. CONTRACT MAINT WAS CALLED AND REPORTED THAT HE GOT SEVEN MORE TURNS OF THE BOTTLE VALVE. I DO NOT CONCUR WITH CONTRACT MAINT FROM WHEN MY SUPVR CALLED AND REPORTED THIS INFO TO ME AT XA:00 PM. I STATED THAT EVERYTHING WAS DONE PER THE MAINT MANUAL SO I TALKED TO TWO OTHER SUPVRS TO GET MORE INFO TO SEE IF THE VALVE MALFUNCTIONED ON THE BOTTLE.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE NEW COMPOSITE BOTTLE WAS INSTALLED PER THE MAINT MANUAL AND THE BOTTLE VALVE WAS TURNED TO OPEN USING HAND FORCE. LATER THE RPTR WAS ADVISED THE BOTTLE VALVE WAS ABLE TO BE TURNED ANOTHER SEVEN TURNS. THIS NEW COMPOSITE OXYGEN BOTTLE; WHEN BEING FILLED; HEATS UP SLIGHTLY AND CAUSES THE SHUTOFF VALVE TO STOP TURNING TO THE OPEN POSITION SHORT OF FULL OPEN. THE VALVE CANNOT BE FORCED BEYOND WHERE IT STOPS.

Data retrieved from NASA's ASRS site as of January 2009 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.