A good example is what helicopter flight school Hillsboro Aero Academy teaches its students: the concept of the en-route descent point (EDP). Before taking off, the student has to specify their particular EDP on a written form, and it varies depending on their experience level.
For example, a relatively low-time student might create an EDP that says, “If I have to reduce speed by five or more knots twice,” (typically due to deteriorating weather), “then I will either land or turn around.” Another example is that if the pilot finds himself lowering the collective two times or more and, due to the lower power output, descending 200 feet below the flight-planned altitude, then he would turn around or land. The fixed-wing analog might be descending 500 feet below the planned altitude and slowing 15 knots below cruise speed, but that also could depend on the type of airplane.
Hillsboro Aero students make a pledge to adhere to their EDPs before taking off, and because they have helped set the parameters and are comfortable with them, they are more invested in complying. The idea is to give new pilots a reasonable way to decide to make the right move to preserve safety instead of just pushing on in the hope that conditions will improve.
What I like about Hillsboro’s EDP concept is that it forces students to think about what they are doing instead of blindly blundering on into deteriorating conditions. And the fact is, in real life, deteriorating conditions can be awfully hard to determine precisely. Rarely do pilots face a wall of clouds; more often the visibility gradually gets worse and worse until they find themselves fully engulfed, and by then recovery is difficult if not doubtful.
Another example of a decision point is having a plan that allows for aborting the takeoff if the airplane isn’t performing properly. If the airplane doesn’t reach 70 percent of takeoff speed by the runway midpoint, the takeoff should be stopped. This decision point assures plenty of runway to stop if the engine isn’t delivering the necessary power and acceleration is sluggish. Note that achieving the 70 percent number at the halfway doesn’t necessarily mean that the airplane will be able to take off and climb well, so be prepared ahead of time to decide what to do. A decision point is useless if it isn’t adhered to.
It’s not necessary to apply decision points to all aspects of our flying, and we also need flexibility to change plans when necessary. But decision points can remove confusion when there isn’t time to dither and help maximize safety margins.