Admittedly I cannot speak from a pilots perspective relative to what a pilot should or should not do regarding a chip light. However this thread keeps returning to what you would do if you have an engine chip light with most of the posts addressing helicopters with more than one engine. By definition on a dual engine helicopter or a helicopter with two power modules the engines / modules are redundant. This redundancy may not be apparent under certain conditions, as on occasion the second unit cannot maintain flight and the helicopter must land. However on a helicopter the transmission has no redundancy and that goes for the driveline as well. On a Boeing-Vertol tandem helicopter if one gearbox goes out for any reason all is lost and the same goes for a K-Max as well. Gearboxes can fail catastrophically without warning and in those cases a chip warning may not be indicated. This may have been the case with the Boeing-Vertol crash in the North Sea several years ago. In the illustration of the Italian SH3-D above the pilot got the warning and an instant later he got the failure. The EH-101 is designed to survive a total lock-up of the transmission but in the process may very well destroy much of the main rotor but that is a subject for another thread.
The reliability and survivability of a helicopter dynamic system and its’ driveline are a function of proper design, proper material selection, proper manufacturing, proper assembly and proper quality control and eventually proper maintenance. Every once in a while one of these elements will come into question and a failure will manifest itself. The extent of the failure and how it manifests itself is a crapshoot and your ultimate survivability of this failure is dependent upon your response to the warning. That is why the designer put chip lights on your instrument panel and to provide further protection they provide a press to test switch.
You have a choice. Respond to a chip light or be protected by an AD that modifies your transmission with this AD having been written in response to a catastrophic failure in which a helicopter and its’ crew were lost as a result of that pilot not responding to a chip light.
If I come across as a doomsayer that is the nature of the business I am in.