Our ONS-15454 chassis are approaching 10 years old and we have started to see fan failures. But when a fan fails, it does not create an alarm within the CTC or generate a remote alarm. We do see the "Fan Fail" light on the fan tray illuminate, but that's it. The only way we know there is a fan failure is noticing the "Fan Fail" light while onsite. We have tried different alarm settings but nothing will report or show up as a failure on the CTC. All of the FAN related alarms are set to Critical. We are running version 9.1. Any ideas how to make the fan failures alarm out and show up in CTC?