What was found
DURING CRUISE, THE FLIGHT CREW OXYGEN GAUGE INDICATED ZERO. AIRCRAFT RETURNED TO SFO AND LANDED WITHOUT INCIDENT. REPLACED THE OXYGEN PRESSURE TRANSDUCER, OPERATIONAL CHECK GOOD.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
DURING CRUISE, THE FLIGHT CREW OXYGEN GAUGE INDICATED ZERO. AIRCRAFT RETURNED TO SFO AND LANDED WITHOUT INCIDENT. REPLACED THE OXYGEN PRESSURE TRANSDUCER, OPERATIONAL CHECK GOOD.