Emergencies are rare, but they happen quickly, and being prepared maximizes the likelihood of a good ending to the day. Of the many numbers associated with flying, the best glide speed is one of the most important. The best glide speed allows you to glide the farthest, giving you time to investigate and fix an issue and find the best place for an emergency landing. Having that number at the forefront of your mind when trouble arises can mean the difference between making it to a good landing site or not. Just make sure that you also consider wind directions. If you’re flying into a strong headwind, you may not make it to your desired landing spot.
There is also a number called minimum sink, which is commonly used by glider pilots. This is the speed that will allow you to stay in the air the longest. If you have a good landing site within easy gliding distance, you may want to consider using the minimum sink speed. It will maximize the time you have in the air to investigate the problem and attempt to fix it. Minimum sink is, however, generally not published for powered airplanes. You can figure yours out by going to a safe altitude and experimenting by pulling the power and noting the descent rate at different speeds. You will notice that, as you get closer to stall speed, the descent rate will increase rapidly for each knot you slow down.
It is important to remember that if you think you are coming up short of your selected emergency landing site, pitching up from best glide to minimum sink will only extend the time that you are thinking to yourself, “Oh no, I’m not going to make it!” You’re best off staying at the best glide speed.
Before you take off on any flight, make sure you know the best glide speed and the minimum sink speed for the airplane you are about to take to the skies. It is a good habit to write those numbers at the top of your notepad so that you have them right in front of you if the engine quits. If nothing else, it is likely good insurance that it won’t.
