B767-300 and 300 ER
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Communication Breakdown; Other / Unknown
Aircraft Equipment Problem Less Severe
General Maintenance Action
Human Factors; Aircraft
It was brought to my attention by the oncoming CA (Captain) that MX (Maintenance) had discovered the crew O2 (Oxygen) level was low. MX had also found; sometime after our arrival; that the O2 valve was in the closed position. To the best of my knowledge; the proper O2 checks were done before we left [our departure field]; including the 10 second bleed test that was done by my FO (First Officer); with no abnormalities noted. We did not note any discrepancies upon arrival; although neither the FO nor myself recall checking the O2 level after landing; as this is not included in any post flight duties. I would suggest closer attention be paid to the O2 levels in flight. This does take a conscious decision as this page is not normally displayed in flight. Do not make assumptions that proper MX procedures are followed; as the logbook was stamped that it was approved for return to service. Always back yourself up.
The reporter explained that there were no problems with the oxygen system during his flight. After the flight (about 2.5 hours after he left the airport) he was contacted by the oncoming flight crew who said the Crew O2 level was low and the O2 valve was in the closed position. He had no idea how that could have happened. The on-coming crew suggested he file a report even though he did not detect any anomalies during his flight.
B767 Captain reported that the crew O2 level was found low during pre-flight by the next crew on the aircraft.