If you request a GCA for a APP or ACC position, the validation will be first on the tower position, as stated in the GCA-regulations of the swiss division. (Example: You request an ACC GCA, you will have a checkout on TWR, APP AND ACC)
An aircraft flies from Birrfeld LSZF to St. Gallen-Altenrhein LSZR, it likes to cross LSZH CTR. What is the correct phraseology for the pilot, and for the controller?
The aircraft has to do an initial call.