How to prepare on type rating
 

I will start with my type rating (turboprop or jet) within now and 3 months.

How do I prepare ?

Do you know which type exactly? A good start is to get hold of a flight manual and study the systems, so that you can concentrate on flying the machine when you do the endorsement.

It often makes little sense studying the procedures an operator uses - hours of mind-numbing reading which equate to 30 seconds of cockpit checks!