Any Unknown or Unlisted Aircraft Manufacturer
Troubleshooting; Training / Qualification; Situational Awareness; Physiological - Other; Communication Breakdown
Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors; Company Policy; Environment - Non Weather Related; Equipment / Tooling
[Our] Flight Training Center utilizes three DEL-MONOX compressed air purification systems to supply breathable air to the oxygen masks in six flight simulators. Pilots breathe this air during flight training events. During routine inspection a technician noticed bright yellow coloring of the media inside the towers of the air purifiers. On each of the three air purifiers there is a placard that states; 'DANGER! Yellow color inside towers indicates unsafe breathing air. Do not use purifier if any yellow color is visible.'   Upon discovery of the significant yellow color in the towers and after reading the DANGER placard I shut down all three air supply systems; entered a discrepancy report for each affected simulator; and notified all maintenance supervisors as well as the manager. On my next return to work day I was informed that a contractor had tested the air and that it was perfect and that some yellowing is fine. The air systems were placed back in service and the discrepancy reports were closed. The next day I was informed that the air contractor had returned and replaced the yellow media in one of the systems because of an alert in one of the quality safety-check systems. My supervisors stated that they knew of no plans to change the media in the other two supply systems. Of greatest concern is the fact that the manufacturer's DANGER placards have now been removed (peeled off) all three supply systems. My supervisors informed me that the contractor is the expert and therefore qualified to assess the air quality and remove the manufacturer's DANGER placards.
When the reporter; a simulator Maintenance Technician; noted the presence of yellow contamination in the media of the three compressed air purification systems distributing breathing air to the simulator oxygen masks he disabled them in compliance with an adjacent 'Danger' sticker advising such a yellow contamination indicates an unsafe condition. The next day he noted all three purifiers back in operation; the yellow contamination still present in two of them but the 'Danger' stickers removed. He was advised by his managers that the purification system contractor was the expert and deemed the status of all three systems acceptable and was qualified to remove the 'Danger' stickers.