This is an instructor demonstration of how to fly a practice precautionary in the U-2. You would do a precautionary if you have a known or possible issue with the engine and you don’t know how much longer your engine will stay running (for example, you lose oil pressure). You will configure the aircraft for a safe landing with partial flaps and can use drag if it’s still available (such as spoilers or speed brakes). The engine will be at or close to idle. The aircraft is also flown so it can make a safe landing, even if the engine quits. You don’t want to put yourself in a position where you need power to make the runway, but you also don’t want to be so high that you overshoot the runway.
A couple key terms:
Aimpoint: The aimpoint is the point you want to arrive at 10 feet above the runway. For this pattern, it’s 20% the length of the runway, or 2400 feet down the runway
High key is the point 2000 feet above your aimpoint, adjusted into the wind, where you’ll commence the final spiral down to land.
Low Key is the point halfway through you’re final spiral down, where you are beside your aimpoint, adjusted for winds, and 1000 feet above the ground