Question: How do you know when to start your descent? At my home airport I plan my descents by using landmarks—be at this altitude over the water tower because that will put me at pattern altitude, etc. How am I supposed to do that when I go to an airport that I am unfamiliar with?
Answer: You have just described knowing the top of descent—that is, knowing how much time and distance it will take you to reach the predetermined altitude, such as the pattern.
