What was found
AIRCRAFT ARRIVED WITH AN OXYGEN LEAK. THE ALTIMETRIC VALVE WAS REPLACED. THE REPLACEMENT VALVE ALSO LEAKED. THE THIRD VALVE INSTALLED DIDN`T LEAK IN THE OFF POSITION BUT WHEN THE PASSENGER OXYGEN WAS TURNED ON DEPLOYING THE MASKS THE VALVE LEAKED FROM THE PRESSURE RELIEF VALVE. THIS VALVE IS LOCATED IN THE COCKPIT ABOVE THE HEADLINER IN CLOSE PROXIMITY TO NUMEROUS ELECTRICAL SWITCHES. AN OXYGEN RICH ENVIRONMENT IN THIS LOCATION COULD BE DISASTOROUS. THIS VALVE SHOULD BE RELOCATED TO THE CABIN TO ELEMINATE ANY HAZARDS.