None. A department head is selected from the junior corps of officers. There is no actual interview process. My year group was 100% selection. Younger year groups are down to an 80% first time selection. There is no need to worry about the interview process.

The interview process was very simple. The recruiter already had all my information and knew what my potential was. They pulled all my information and called and set up an interview. the recruiter came to my house to tell me all the great benefits of joining.