Logansi
No I don't think thats where this is going, although there are other countries that do ishihara plates annually, but if they are getting everyone to do the ishihara plates there must be a reason for that.
The groups of CVD guys we have;
1. Guys who passed the plates years ago who for whatever reason can't pass them now, there could be a medical reason for this (rare) or perhaps they were just good mates with their doc.
2. The people who passed the PAPI simulation (no longer available) or, the TWR light gun test (i believe thats no longer available also).
3. The guys with restricted medicals who don't pass anything. I understand this group is around 400 pilots.
Add these three groups together (one big melting pot) and we get a bunch of guys who's CVD is not quantified by any minimum standard, and CASA like standards.
I think CASA may want to know exactly what their up against in terms of the numbers that are out there. With the new medical system its easy for them to run everyone through the Ishihara plates for their next renewal only, after that its back to normal. I think they will want to control who gets a medical based on standards.
The science around CVD and aviation supports the CVD pilots, but having no minimum standard fly's in the face of everything that CASA stands for and in fact everything that happens in aviation. I think that is the CVD pilots biggest issue in the coming years. One thing is for sure, this isn't going away anytime soon and I think its going to heat up before it cools down. I think CASA want this simplified probably into either the CAD only or plates followed by CAD. I think the Farnsworth's days are numbered.