It's one thing to be able to know the classical equations of how something works (e.g. Maxwell's equations in this case, or Navier-Stokes is another good examp

It's one thing to be able to know the classical equations of how something works (e.g. Maxwell's equations in this case, or Navier-Stokes is another good example), and quite another to understand the practical dynamics of the system as it evolves through time under boundary conditions that you care about (like the inside of a jet engine).