Narrative:

With approximately two hours of flight time remaining; I heard a sound similar to the sound of oxygen leaking. The sound lasted for only a few seconds; but prompted me to ask the first officer to verify the oxygen level on our crew oxygen bottle. He looked at the gauge on the bottle and the reading was zero psi. After confirming the oxygen level; I immediately called for the emergency QRH procedures. The procedure called for us to descend to FL250 which we coordinated with center. The procedure also called for us to position and make available the cockpit portable oxygen bottle; which was not installed on our aircraft. Due to the missing cockpit pob; we were required to obtain two pob's from the cabin. First officer called the cabin over the interphone and requested the bottles and gave them a brief summary of our situation. The emergency procedure then stated; 'continue flight at fl 250. Consider landing short of destination to avoid extended enroute operation without normal oxygen supply. Contact flight control for new flight plan and amended release as appropriate.' based on this statement; first officer and I discussed the possibility of having an emergency involving cockpit smoke or fire and not having crew oxygen and interphone available. We also considered the remaining flight time. Based on these considerations; we felt a precautionary landing at the nearest suitable airport would be appropriate. At this time; I transferred controls to first officer and contacted dispatch. I explained our situation with dispatch; discussed possible alternatives and options; and ultimately concluded that a diversion to [a nearby airport] would be appropriate. We were updated on the weather and amended our flight plan with the new destination. First officer began coordinating the diversion with center and I briefed the flight attendants and passengers on our situation and plan of action. Dispatch called ahead to our station and planned for our arrival. The remainder of the flight proceeded without further incident and the diversion was successful. We offloaded the passengers and customer operations planned a rescue flight for the passengers to proceed to their destination.

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Original NASA ASRS Text

Title: An MD-83 Captain reported losing crew oxygen during cruise flight. They diverted to a nearby airport as a precaution.

Narrative: With approximately two hours of flight time remaining; I heard a sound similar to the sound of oxygen leaking. The sound lasted for only a few seconds; but prompted me to ask the First Officer to verify the oxygen level on our crew oxygen bottle. He looked at the gauge on the bottle and the reading was zero PSI. After confirming the oxygen level; I immediately called for the Emergency QRH procedures. The procedure called for us to descend to FL250 which we coordinated with Center. The procedure also called for us to position and make available the cockpit portable oxygen bottle; which was not installed on our aircraft. Due to the missing cockpit POB; we were required to obtain two POB's from the cabin. First Officer called the cabin over the interphone and requested the bottles and gave them a brief summary of our situation. The emergency procedure then stated; 'Continue flight at FL 250. Consider landing short of destination to avoid extended enroute operation without normal oxygen supply. Contact Flight Control for new flight plan and amended release as appropriate.' Based on this statement; First Officer and I discussed the possibility of having an emergency involving cockpit smoke or fire and not having crew oxygen and interphone available. We also considered the remaining flight time. Based on these considerations; we felt a precautionary landing at the nearest suitable airport would be appropriate. At this time; I transferred controls to First Officer and contacted Dispatch. I explained our situation with Dispatch; discussed possible alternatives and options; and ultimately concluded that a diversion to [a nearby airport] would be appropriate. We were updated on the weather and amended our flight plan with the new destination. First Officer began coordinating the diversion with Center and I briefed the flight attendants and passengers on our situation and plan of action. Dispatch called ahead to our station and planned for our arrival. The remainder of the flight proceeded without further incident and the diversion was successful. We offloaded the passengers and Customer Operations planned a rescue flight for the passengers to proceed to their destination.

Data retrieved from NASA's ASRS site as of April 2012 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.