"How does one determine a safe altitude to return to the airport in the event of an engine failure on takeoff? Practicing this emergency does not seem feasible." - Jon M
“My first bit of advice is simple and very clear. There is an altitude at which a safe return can be made to an airport when an engine failure occurs on takeoff. The trouble is, it is not the same altitude for every pilot in every aircraft on every day! So, if you don’t know what that altitude is when the engine failure occurs, do NOT attempt to return to the runway – the price of failure is severe!
Having said this, you can practice the return to the airport maneuver safely at altitude with your instructor to get a sense of what the maneuver involves.
(At a safe altitude) select an imaginary runway behind you as a target. Fly directly away from it at departure airspeed and configuration. Smoothly retard the throttle to idle (don’t forget carb heat if appropriate) and lower the nose to pick up the designated airspeed for engine failure in your aircraft.
Remember, a simple 180 degree turn will not align you with the runway. And, you will most certainly have a tailwind. Consider the challenges of looking over your shoulder for the runway at low airspeed while maneuvering with a failed engine. Might your recent proficiency come into play?
The correct procedure for engine failure on takeoff is to lower the nose and land straight ahead. But there is a safe altitude for every pilot to attempt a return to the airport. Practice can help you determine this altitude, but it should include a generous safety margin due to the complex nature of this maneuver and its disastrous downside!”