How would you estimate landing distance on a wet runway for a narrowbody using published data?

• A. Use published landing distance data; apply corrections for weight, speed, braking action, and reverse thrust per AFM guidelines.
• B. Rely on guesswork for landing distance on wet runways.
• C. Ignore published data and assume the dry runway distance.
• D. Use only the speed correction, ignoring weight and braking action.

Answer: (B)

When estimating landing distance on a wet runway, you start with published performance data and then tailor them to the actual landing conditions you face. Those published figures are generated under controlled conditions and for specific configurations, so they give a reliable baseline rather than a guess.

Because a wet surface reduces braking effectiveness and increases stopping distance, you apply corrections from the AFM based on several factors. First, the actual landing weight matters: a heavier airplane has more kinetic energy to dissipate, so the distance increases. You look up the data for your weight (or interpolate between data points) and note the baseline distance for a wet condition. Next, the reference approach and landing speed influence distance: if you arrive faster than the reference speed, you must apply a speed correction that lengthens the landing roll. The braking action or runway contamination level is also critical; if braking action is poorer than the chart assumption, add distance accordingly because friction is reduced. Finally, the use of reverse thrust affects the distance: when reverse thrust is available and applied as per the AFM, it reduces the landing distance; if you rely less on reverse thrust, the distance increases.

In practice, you would use the published data for a wet or contaminated runway, adjust for weight and speed differences, apply the braking action correction, and account for reverse thrust as specified. The resulting figure is then compared to the runway length to confirm a safe landing margin.

Relying on guesswork or ignoring published data is unsafe and not consistent with standard procedures, because it ignores how runway conditions, weight, speed, and thrust influence stopping distance.