When a child reaches the height of 135 cm, it’s allowed to sit as an adult in a passenger seat with no airbag. However, it’s safe for a child to sit like an adult in a passenger seat with an airbag only once it’s 140 cm tall. Children below 135 cm are to be secured using special safety seats, which eliminate the requirement for the airbag. If the airbag is triggered, it will very forcefully push the child safety seat against the front seat. This will cause a great impact on the child, and in addition traps the child. Therefore child seats should not be installed without disconnecting the airbag first. The airbag does however not necesarrily have to be removed, it’s sufficient if you deactivate it.