I believe the CAD test duration is variable depending on how bad your colour vision is.
.e. if you are not colour normal it presents further sequences to determine your type and severity.
I tried a CAD test when I was in the UK 2 years ago and it went for at least 40minutes and my eyes were extremely tired by the end of it - it was a marathon and no fun at all. Its just another colour vision test - nothing to do with the task of piloting an aircraft.
Last edited by outofwhack; 13th June 2012 at 12:11.