Jan Olieslagers
As to "High Key" and "Low Key"
I've had the privilege and honor in my life to both fly civilian and military. In my early civilian flying days when being taught the emergency procedure for engine failure it was always....Land in a field. More of a TLAR (that looks about right) approach. Now yes you pitched for the best glide and basically picked out a field and orbited above it until you landed. That that sounds like a good plan, but where exactly should you be in that orbit above the field?
In military training I've learn a specific ELP(Emergency Landing pattern).Think of "High Key" as and an actual point you fly through in the sky. Like a huge ring in the sky that you are trying to fly through directly abeam your intended point of landing. If you're in the right seat that would be to the left of your intended point of landing if in the left seat to the right of the intended point of landing. This way you can always keep in sight where you're landing. Now this may be different for every aircraft, but what worked great for the C-172 at 2200lbs is 2,000'
"Low Key" is like a base leg to final, which is approximately 1000' feet for a C-172 at 2200lbs.
You are then looking to be approximately 500' rolling out on final and then you S turn or slip the aircraft to lose any extra altitude if you have any.
The issue with TLAR and just orbiting over the field is what if you're too high or what if you're too low? Will you know if you are? If there are 150' trees you have to miss (which I had) will you make it?
Knowing exactly where to be and what altitude to be at will let you know that you're on a good glide profile and will help increase your chances for a safe landing.
Here is a blank ELP (emergency landing pattern) diagram. I recommend taking what ever aircraft you will be flying and climb up above your home airport to about 4,000' AGL and orbit at best glide to see what your actual numbers will be for an entire 360 orbit and then add a bit of altitude to that for safe measure. This will be your "High key" and "Low Key" numbers.
Hope this helps.
God bless,
Tony<><
P.S. 4 days after my engine failure my wife and I found out we are going to be parents!!!! Super excited!!!