Originally Posted by
Mitchaa
My understanding is that HUMS is mandatory in the UK on all oil and gas helicopters as directed by the CAA in CAP753?
In Europe, I don't believe there is any such legal requirement to have HUMS fitted, however in general the majority do as it's a customer requirement (not a legal one) I don't think EASA have made it mandatory but I may be wrong?
We don't hear about the 'HUMS successes' we generally only hear of the failures.
But yes, you're correct, if it is a transmission related failure and it's proven that VHM could have caught it, then you never know, they may introduce it as a mandatory requirement in EMS too.
I've forgotten where the rule is right now (JimL will have to tell us!) but amongst other things, it's part of the dispensation to continue non-compliant with PC1 over hostile terrain offshore. CAP753 is really just the acceptable means of compliance, not the rule itself.
UMS is useful for detecting that on the previous flight, the crew didn't overtorque, overtemp the engines etc and is obviously much easier to achieve than VHM because, certainly in a modern helicopter, the necessary data is already present on a data bus. VHM of course requires the fitting of numerous vibration transducers and lots of wiring, plus a not insignificant effort to set and refine the thresholds.