JAR:
First - you will need a type rating for that ME helicopter ( on which you want to fly your training). Or not, if you are already type-rated on that type of the helicopter.
Second - your SE/IR-H must be valid because you are doing "an extension" from SE to ME / IR ( itīs connected )
Third - after all of that, you will need to fly a least 5 h on ME helicopter for ME/IR-H
(I am not sure how much can be on FFS or FNPT, who knows ? )
JR
