When a damaged engine or fuel tank have a fire effect attached, it will generally be accompanied with an illumination source which lights up part of the plane. While the engine and tank light source are separately defined, for each there is just one intensity for all related fire effects attached thereto.
I've recently incorporated the switching to a smaller fire effect when the fuel tanks run dry. Having accomplished that, and after noting the discrepancy between the now smaller/dimmer fire and the former, prominent illumination source, I just had to try to find a way to also switch to a lower intensity light source to accompany the lesser fire. It's taken perhaps 15 hours of cudgeling my brain pan, but dogged persistence has paid off. Now when the fuel tanks go empty and the engine(s) wind down, a smaller fire is invoked and the attending illumination decreases.
(I have a thread tracking my Java progress in the Super School.)
In the screenie below, the upper panel shows the much dimmer illumination accompanying the smaller fire effect. I'll brighten it somewhat; I made it quite dim initially so as to ensure telling it apart from the 'normal' illumination while testing.