Calculating FTTFd

[ALAN13]

So we use the MILHDBK 217F. in this standard is a calculation that taking into account the wattage of the component divided by the wattage used across that component.
Now this standard is really obsolete and some people use the FIT values given by manufacturers . The problem with this is that it doesn't take into account how hard you drive that component I.E the wattage over the wattage used