Provide measureable tell-tale instructions in maintenance procedures

[MikeS]

Here is useful advice that will help you write world class maintenance
procedures. For this example we look at some recommended maintenance
actions for a mining operation's truck fleet.

To protect the gearbox the following wording is common. “Prevent
abuse shiftings”, “Prevent overloading and drive to conditions” or
“Correct greasing”. It is more meaningful and useful to be specific,
so that the actions are clearly measureable. As examples, I will
reword these three recommendations so that it is clear when they are
done correctly and the task requirements are observable and
measurable.

“Prevent abuse shiftings” could be improved by rewording it to, ‘Bring
engine speed up to between 2000RPM and 2250RPM, and at steady speed
shift gears’—the necessary behaviour is absolutely clear to the
operator and you can measure their performance.

“Prevent overloading and drive to conditions” could be worded as two
separate requirements First, ‘Load vehicle to ± 5% (plus/minus) of
design load’—the design load will be provided by the manufacturer. If
you can actually mark the right load height on the vehicle, the best
would be to say, ‘Load vehicle to ± 100mm (plus/minus) of maximum load
mark’ (You would need to ensure that 100mm is 5 percent of design
load.) Second is to specify to the driver that their behaviour
matches the driving conditions. Fundamentally we are concerned that
the truck is not overstressed no matter the conditions it is
undergoing. You need to find tell-tale signs for the driver to
observe that will provide the feedback to control their behaviour. A
combination of RPM and acceleration would be useful variables to
measure during all operating situations. The driver would need to
meet both the RPM limits and rate of speed change limits in their
driving behaviours.

“Correct greasing” maybe better said as, ‘Pump grease recommended by
manufacturer into shaft universal joint until you see grease exiting
excess grease hole’. If there is no grease hole you will need to
specify another way to know that enough grease has been injected into
the item needing grease.

When you give maintenance instructions always make clear exactly what
you want people to do in a way that they can measure for themselves
and know how well they are performing. This lets them self-manage and
self-learn—they will seek new answers if their current practices do
not produce the required results.

Best regards,

Mike S.