Thank you Sid....it really was a simple question and equally simple answer.
There is a fuel level (varies by aircraft and operator as well as by the individual pilot) that is seen as the limit to which we will fly to before being forced to make a landing and if we comply with that concept....the Engine(s) continue to run normally until we are safely on the ground.
Might we consider in the 135....the appearance of a Red Warning Light saying "Low Fuel", especially if lower than that arbitrary fuel level said to be the Minimum Fuel Level allowed for continued flight, should illuminate....it being a separate system to the Quantity system....the aircraft should be landed unless already on short final to the heliport (or very nearly so....like literally one or two minutes)?