Mitchaa
"An alert over a threshold will be reported by the line engineer on download "
You missed my point mate, HUMS is only useful IF the failure happens to be a parameter monitored by the HUMS and for which there is a threshold set. Thankfully failures which are not detectable by a HUMS threshold are reducing, but all the same, they are still there. Thats not a negative reflection on the engineers at any organization, merely a limitation of HUMS.