Aviation checklists are typically clipped to a knee-board that secures to a pilot's thigh. When I was asked to do this project, I insisted that in order to properly execute the design of this app I would first need to take a ride on a small aircraft. I had only been on commercial airlines previously, so I asked all kinds of questions and got to know the situations in which you'd use these checklists. As it turns out, you use them every flight: before, during, and after.
Night Mode / Emergency Mode
Because the app was going to see a lot of usage at night, I proposed a night-vision mode that made the screen more bearable to look at in the dark. There was also a different aesthetic for emergency mode, so that you'd never accidentally wind up performing emergency procedures mid-flight.