As a current employee of the company, I was already familiar with the hiring process. However, I wasn't exactly expecting to be treated as a new hire. I interviewed with the program manager, team leader, two engineers, one technician and the HR manager. That's a lot of talking, sitting, listening and thinking - over a three hour period with no breaks. You should be prepared to answer a lot of the same questions and be honest - these guys don't mess around because the interview process is just as time consuming and stressful for them. The interviewers will collaborate after the meetings and make decisions based on your education, your past or present work experience, your answers and confidence in your abilities. Should you be an employee, your current supervisor will also weigh in with comments regarding work performance.
Then you wait. Be prepared to wait a very long time unless the need is immensely important. Be aware that many companies ebb in and out of hiring freezes based on their quarterly performances. This was the case with my interview process which caused a three week "dead air" span in communications between myself and the HR manager. More on that later...