How are spare parts selected?
Four decisions, taken in order, that narrow the choice to the right spares to hold so a failure is put right quickly.
A spare is only useful if it is the right part, in the right place, when a failure happens. The failure rate shows how many to expect, the impact of a failure decides how close they must be, the replacement must match the original exactly, and the way the spare is kept and recorded decides whether it still works when it is needed.
The flowchart only narrows the choice. The final list is agreed against the airport’s maintenance programme for quantity, stock location and restoration time, and against the manufacturer’s data for type, rating, connectors and seals.
Frequently Asked Questions
Q1How are AGL spare parts selected?
By working through a few decisions in order: how often the part is likely to fail, what its failure puts out, what the replacement must match, and how the spare will be kept and recorded. The result is then agreed with the airport’s maintenance programme and the manufacturer’s data.
Q2How many spares should be held?
There is no single figure. The number comes from how many failures to expect, which is the total operating hours of all the units in service divided by the MTBF (for lamps, the rated life is used instead), from the site’s own failure history, and from how fast a replacement must be fitted. Remember that MTBF is an average over many items and not a promise about any one.
Q3Why do critical parts need spares on site?
Availability counts how long a failure lasts as well as how often it happens. A part whose failure darkens a whole circuit, such as a CCR or a primary connector, costs far more per hour than one that darkens a single light, so the replacement must be close at hand and quick to fit.
Q4Why must a spare match the original?
A different lamp type or wattage changes the output and the load on the isolating transformer. A replacement transformer needs the same current ratio, a suitable power rating and compatible connectors. An LED module, its optics and its driver are matched, so only the approved part is fitted.
Q5What should be checked before the choice is final?
That each spare matches the type, rating, connectors and seals of the part it replaces, that the quantity suits the failure history and the restoration time, that it will be stored clean, dry and identified within any shelf life, and that the asset register and warranty records are kept up to date. The manufacturer’s data decides.
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