VFR Day & Night Requirements and Inoperative Equipment

Let’s say you’re just beginning your preflight inspection. You walk out to the airplane, turn on the lights, deploy the flaps, and during your initial walk around you discover the right strobe light is not working. Can you go fly? What if the spinner was missing? or the attitude indicator was inoperative? When asked the question, “who is responsible for determining the airworthiness of the aircraft?” What comes to mind first?