Part 91, gives us lots of discretion when it comes to choosing an approach, deciding if it’s legal (and safe) to continue, and then if it’s legal and safe to land. The caveat is that personal judgment, often in the heat of the moment, becomes the catchall for critical phases of flight. This makes us susceptible to pushing that discretion beyond what (in hindsight) we might consider legal and/or safe. Add a little bad luck and the likely outcome is a mishap—or worse.
Take the runway overrun, one of the most common causes of non-fatal IFR accidents. Pilot judgment is a constant throughout the approach and landing, and any variables popping up so close to the ground must be addressed instantly, making for higher risk. Still, hard numbers are constantly in play: Ceilings and visibility; runway length, approach minimums, and, to a certain extent as we’ll see, aircraft performance.
