Landing on a Contaminated Runway with a Go-Around Limit
Landing at an airport with LDA 2,600 m, runway 27, tailwind 15 kt, runway condition 5 mm water and medium braking action. Landing mass is 62,000 kg. The AFM factored landing distance required, already including the tailwind and planned configuration, is 2,150 m dry, 2,480 m wet and 2,950 m contaminated. Company procedure gives no credit for reverse thrust and requires autobrake max. OAT is 35°C, pressure altitude 1,000 ft. The landing climb limit mass is 61,000 kg and the approach climb limit mass is 60,500 kg. Fuel on board is 3,000 kg; diversion fuel is 1,200 kg; final reserve is 900 kg. The destination weather is improving but the runway water is not expected to clear for 30 minutes. The crew must decide whether to land, hold, or divert.
1. Determine whether the landing is legal using the factored distances and the 15 kt tailwind. Show the comparison.
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Compare factored landing distance required with LDA. Dry 2,150 m is less than 2,600 m; wet 2,480 m is less than 2,600 m; contaminated 2,950 m is greater than 2,600 m. The actual runway has 5 mm water, so the contaminated figure applies, not the wet figure. The 15 kt tailwind is already included in the quoted distances. Therefore the landing is not legal: the required distance exceeds LDA by 350 m. Improving weather does not change the current contaminant. Hold, divert, or wait for the water to clear and recompute. Do not use the dry or wet figures as a substitute.
2. What is the effect of reverse thrust, and can it be credited to make the landing legal?
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Reverse thrust is not credited in the AFM factored landing distance under company procedure. It can reduce stopping distance and brake heating after touchdown, but it cannot be used to make an otherwise illegal landing legal. Use full reverse after touchdown, maintain directional control, and be prepared for asymmetric reverse on a contaminated runway. Autobrake max and spoilers are the primary stopping means. If the crew is relying on reverse thrust to stop within LDA, the landing should not be attempted.
3. The airport OAT is 35°C and pressure altitude 1,000 ft; landing climb limit mass is 61,000 kg and approach climb limit mass is 60,500 kg. Actual landing mass is 62,000 kg. What does this mean for the approach?
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At 62,000 kg the aircraft exceeds both the landing climb limit of 61,000 kg and the approach climb limit of 60,500 kg. That means the scheduled go-around or balked landing climb gradient is not assured at the actual mass. The approach should not be continued to landing because a go-around may not clear obstacles. The crew must reduce mass below the limiting value or divert to a runway or airport with better conditions and performance. Holding to burn fuel may reduce mass, but the contaminated LDA still fails, so diversion is the safer option. A landing is not acceptable without both landing distance and climb performance.