airman1 -
I know you can still hold a Class 1 even if you fail the colour plates
It depends.
If you're unlucky enough to be one of those that can't tell the difference between green and red you're screwed as the final test for a pass in the class 1 if you're color blind is going to the airport and getting ATC to shine the indication lights at you, if you can't tell them apart - thanks for coming.