Crosswind landing on a contaminated runway
Aircraft mass 62,000 kg. Dry runway landing distance (factored) 1,700 m; runway available 2,400 m, with 1,100 m of it covered in 5 mm standing water. Wind reported 090°/18 kt gusting 28 kt, runway 06 (060°). AFM gives a 15% landing-distance increase for 5 mm standing water and a 10% increase for a 10 kt tailwind component on the dry figures. Braking action reported medium.
1. Compute the crosswind and headwind/tailwind components and assess the landing.
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Wind 090°, runway 060° → 30° off the nose. Headwind component = 18 × cos30° = 15.6 kt (gust 28 × cos30° = 24.2 kt). Crosswind = 18 × sin30° = 9 kt (gust 28 × sin30° = 14 kt). So it is a headwind, not a tailwind - the 10 kt tailwind penalty does not apply. Crosswind 9 kt steady, 14 kt gust - check against the AFM crosswind limit (typically 25–35 kt for this class), so within limits. Landing distance: apply the 15% water penalty to the dry factored distance: 1,700 × 1.15 = 1,955 m. That is less than 2,400 m, so the landing is feasible, but the medium braking action and standing water mean the actual stopping performance could be worse than the book figure.
2. What operational precautions apply given the standing water and gusty wind?
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Use full flaps and a firm touchdown to break through the water film; avoid reverse thrust asymmetry on a contaminated surface; be prepared for aquaplaning - at 5 mm standing water and typical tyre pressures, dynamic aquaplaning is possible at higher speeds. Add gust correction to Vref (half the gust factor, not more than 15 kt). Plan to land into wind on the 1,300 m dry portion if the water-covered portion can be avoided, and be ready to go around. Confirm the reported braking action with the tower and check the runway length again after any change in wind.