MNT.4:4 - Solution

Name the condition question first. Identify the functioning or failure concern and what a different answer would change. A request to interpret today’s alarm can often be answered from existing observations; it does not automatically justify a new monitoring programme.

Recover the measurement basis. State what is measured, the unit and relevant measurement location, method, sampling window and operating state. Establish instrument and inspection limitations that can change interpretation. A vibration trend under changing speed needs a comparison appropriate to that change; the same displayed number does not establish comparable condition.

Find the relevant reference: an applicable baseline, a specialist interpretation, a known operating relation or a justified threshold. Distinguish an action threshold from an instrument’s display range or a convenient colour band. Preserve the basis for the threshold and the action it is intended to support. Numerical limits for a real machine come from the applicable equipment and use evidence, not this framework’s examples.

Reconcile conflicting channels by their subject and conditions before averaging them. A local temperature rise and a vibration change can concern different mechanisms. A sensor replacement can explain a discontinuity. Missing data can mean a lost measurement, a stopped machine or an unobserved interval; choose only the interpretation that the available evidence supports.

Return three claims separately where needed: what was observed, what condition is inferred and what is forecast. For a forecast, state horizon, future-duty assumptions and uncertainty relevant to the decision. If those assumptions do not cover the planned duty, limit the forecast’s use instead of presenting its central estimate as a deadline.

Consider whether more monitoring is worthwhile. Ask which obtainable observation could change the maintenance response, when it would arrive, whether interpretation and response capability exist and what work it would displace. A technically improved predictor needs a maintenance-use gain to justify deployment. Conversely, a simple repeat measurement can be valuable when it cheaply distinguishes a changed instrument from a real deterioration.

Complete the condition account with its supported interpretation, material limits and response or return point. If the interpretation is adequate for the receiving question, stop. A condition account can recommend returning to diagnosis without prescribing a particular repair. For consequential assurance, examine the measurement’s applicability and the reasoning that connects it to the claim, using C.16 and A.10 at the required scope.