Hi Soave_Pilot,
depending of the engine(s) in your helicopter and depending on the flighthours you will do - an engine chip is a more or less common occurence.
Some have chip- or fuzzburners fitted, so before you go for an outside or emergencylanding, you can burn of the stuff on the magplug - and if it isnīt staying on or comes on a second and third time, you continue the flight.
If it stays on, it depends on further values, if you want to put it into ground idle and back to power for landing - or shut down the engine (talking about twins here).
Still, the magplugs are fitted, to tell you, that something is wrong with your engine (or gearbox).
Most times it will be parts from manufacturing or overhauling, that come loose after a while and are no big deal - but sometimes there are bearings and other parts in the engine, which start to break apart.
So you have to consider that every time you get an indication.
Itīs good to know, where the magplugs are, so that you can take a look at them - saves the engineers some time. Best have a talk to them, I think they will show you how, and what to think about (keeping the stuff on the magplug for further examination).
Greetings Flying Bull
(MagPlug indications with me around every 800 to 1.000 hrs)