Probably a good thing that actual understanding is now required as the copyright issue might prove a difficult hurdle to overcome.
A legal minefield for the ATOs?
Having to understand the logic by asking the question WHY.
Prior to JAR when the CAA set the exams the papers were separate for engines, as only piston engines was required for licence issue. Jet engines was only required if you wanted a turbo/jet engine type rating.
PPSC notes were produced by Mike Longhurst, although the Rolls Royce jet engine book was essential reading.
His question bank was 210 questions. I eventually learnt the correct responses to them in a day and scored 90% in the exam.
In the end, it was nothing to do with understanding the subject and asking the question WHY, simply a “Pavlov dog“ response to the question and recognising the answer.
It wasn’t until the type rating did the mists clear and you began to understand WHY.....