Hi!
Well, I see some issues with the drawing. One is that curves could be made smoother, but that's less important one.
What REALLY counts, that the drawing is practically outside the SB/FD style.
To begin with, we use the black contour as an outline, and it has to be uniform black. Your 'black' is actually no less than FOUR different shades.
Secondly, it seems that You've applied that "black" for "outer contour of the painted area", which is not quite the case, as it should be rather "outer contour of the element in question, unless in it particular place it blends smoothly into the part that's (from viewer's perspective) behind it". So essentialy the intake (the 'hole' part) of the engine in the vertical stabilizer, front part of the ducted fan, horizontal stabilizer, upper contour of the wing for at least most of its length should be outlined in black as well. Same for the line separating 'glass' and fuselage and the canopies as well.