quote:

Since we do detective maintenance in time based period can I consider it as branch or under preventive maintenance strategy.

Vee: Detective maintenance finds failures AFTER they have occurred; the aim of preventive maintenance is to catch the item BEFORE it fails functionally. PM is time-based, but all time-based work is not necessarily preventive'

>>Back to the failure what I understood from u that every thing has failure degradation ,if so that’s mean u support the concept of failure pattern “ A” .....<<

Vee: NO, most emphatiocally not! Very few failures follow pattern 'A'. It is one of 3 age-re;ated failure patterns, the others being 'B' and 'C'. In these three, degradtionis clearly observable. That does not mean there is no degradation in patterns 'D,E,and F'. Light bulbs, transistors, ball bearings etc., also degrade due to fouling, fatigue, corrosion, heat etc. The starting point of degradation is not always known or predictable. Similarly the rate of degradation may be slow or very rapid.

>>and u ignore the others since the other 5 patterns mentioned that there is a random failure , without any clear reason <<

Vee: Firstly it is not 5 patterns, only three, D,E and F. Random failure does not mean failure without cause. It only means we dont know its timing, even when we know its cause. Usually, this is due the complexity of the item (i.e. there are many contributing failure modes, not just one).

In addition, the cause can also be unpredictable (incorrectly called random). For example, bird-strikes on aircraft engines, nails causing tire punctures etc can happen unpredictably. Lightening strike intensity can largely be predicted, but not the exact timing or the location. The cause of lightening is well known.

>>like what I mentioned before panels and electronic , which I think the proper strategy for it in some circumstances is run to fail

quote:

Originally posted by Ozgipsy:
Following the RCM logic diagram there is the capacity to assign run-to-failure for hidden failures where the consequences are operational or non-operational, and you have already worked through the applicability and effectiveness criteria of every other step.

quote:

Originally posted by Josh:
Vee, I have asked how to calculate the availability of FFT in your webworkshop presentation matl in the Maint Connctn Forum but may be you didn't see it.