Page 48 - RCM - A practical Guide_V1

RCM - A Practical Guide

• replacing the asset for a more suitable one?
Could we reduce the probability of failure by changing the operating context by:
• changing the way the equipment is operated so that it stays within safe limits
Could we reduce the severity of the consequences of functional failure by introducing a compensating
provision by:
• installing a device to shut down the equipment in the event of failure?
• installing a device to warn the operator of impending failure?
• installing a back-up device to take over the failed function?
Could we change something in the wider support solution that will help to mitigate, avoid or detect
failure by:
• designing a new maintenance procedure?
• a change in maintainer training?
• the provision of a new item of tooling?
Management of redesign activities
Redesign activities, whether in service or in design, isn’t cheap; especially if it involves changes to
equipment configuration. If an item is modified by adding a warning system, for example, this warning
system also requires maintenance (probably in the form of a FF task). So in carrying out any
modification it is possible that maintenance may increase. This new function will require RCM analysis
to ensure acceptable probability of failure or multiple failure.
An analysis, once complete, is continuously challenged and any justifications need to be robust -
especially in the case of redesign recommendations.

No maintenance
***Applicable only for non-safety (none important) failure modes***
Run to failure.
Failure modes that are deemed to be non-safety (non-any other important factor), for which no
applicable or effective maintenance has been identified and change action is not deemed appropriate,
the result is no scheduled maintenance.
This implies that the consequences of failure are either minor or, at least, able to be lived with and
that the failure can be permitted to occur. The failure will be dealt with on a corrective action basis.
The rigorous decision-making process provides a fully documented, justifiable and defensible case for
inaction.
Other task options

Combination tasks
In some RCM standards, SAE JA1012 in particular, it’s suggested that a combination of two different
tasks may be required in order to manage a particular failure mode. These circumstances are rare and
only apply when safety or environmental failure consequences are identified and that no task on its
own can control the failure mode and reducing the risk of failure down to an acceptable level.

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