Two phone screenings, both much of the same. They went over each line item on my resume and asked me to explain each in more detail. The more you explain, the more detail they will ask for. They ideally want to find parts of your project experience to ask you about first principles of physics and engineering. Ex. "I designed this to have a bolt connecting the two parts." Interviewer: "Why did you choose that bolt? What threading fit did you use and why?"