B737-800
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Flight Cancelled / Delayed; General Maintenance Action; General Release Refused / Aircraft Not Accepted
Aircraft; Procedure
Upon arriving at aircraft; noticed the crew O2 supply read zero. I reviewed the AML (Aircraft Maintenance Logbook) and found the aircraft had been on the ground for approximately 5 days. I also noticed the last MX (Maintenance) action taken was to change the crew bottle due to low crew O2. That got my attention. The bottle had been changed 5 days ago and the bottle had emptied while the aircraft sat on the ramp. So; I went further back into the AML pages and found the crew O2 bottle required changing 4 other times in 30 days (meaning this was the 5th time it required changing in a month). This led me to believe there was a deeper problem with the crew O2 system. Therefore; I refused the aircraft. Lack of meaningful automated historical oversight of AML discrepancy/corrective actionAs AMLs are being moved to more remote electronic system with less transparency to the flight crews; a system that compares discrepancy code numbers so that when one is able to detect a system failure that is repeated often. As this aircraft has been imported to the new AML storage system (which is MUCH less accessible to flight crews than the old [software] system); the only reason I was able to see the problem was because the old AML discrepancy book hadn't been removed from the book yet.
Captain reported refusing the aircraft after discovering an empty crew oxygen bottle and after reviewing the AML (Aircraft Maintenance Logbook) that the crew oxygen had been replaced 5 times in the last 30 days.