YOU SAID:

that'll happen when pigs fly

INTO JAPANESE

豚が飛ぶときに起こるだろう

BACK INTO ENGLISH

It will happen when pigs fly

INTO JAPANESE

豚が飛ぶときに起こります

BACK INTO ENGLISH

It happens when pigs fly

INTO JAPANESE

豚が飛ぶときに起こる

BACK INTO ENGLISH

It happens when pigs fly