Landing and Approach Phase
Approach categories and minimums
Approach category is set by Vref (or Vat) at maximum certified landing weight: A = 91 kt or less, B = 91–120, C = 121–140, D = 141–165, E = 166+. Category drives circling minima and, on some procedures, straight-in minimums. DA applies to precision and APV approaches; MDA applies to non-precision approaches, and descent below MDA is not permitted until the required visual references are in sight. RVR may be substituted for reported visibility only where the procedure authorizes it.
Stabilized approach
A stable approach by 1,000 ft in IMC (500 ft in VMC) means: on the correct lateral and vertical path, Vref set, sink rate under control, power set, checklists complete, and a briefing done. If any element is missing, go around - the go-around is always an option and never a failure.
Landing distance and wind correction
Transport-category planning requires the landing distance available to be at least 1.67× the dry runway distance (1.92× for a wet runway, absent manufacturer data), which is why actual touchdown distance is often only 60% of the runway. Add wind correction to Vref: half the steady headwind plus the full gust increment, with a minimum of 5 kt.
Worked example: Vref 130 kt, wind 240/12G20. Steady headwind component 10 kt → add 5; gust increment 8 kt → add 8. Target = 130 + 13 = 143 kt.
Rule of thumb: crosswind component ≈ wind speed × sin(angle); at 30° it is half, at 45° about 0.7, at 60° about 0.87.