Crosswind Landing at a Coastal Strip
A light twin (maximum takeoff weight 2,100 kg) is on final approach to Runway 27, a 1,200 m sealed strip aligned 270°/090°. The automatic terminal information service reports wind 320° magnetic at 18 knots, gusting 27 knots. The pilot's aircraft flight manual states a maximum demonstrated crosswind component of 17 knots and a landing distance of 640 m at maximum landing weight on a dry runway, with no correction published for gusts. The runway is dry, surface temperature 31 °C, and the pilot is 40 minutes into the flight with 90 minutes of fuel remaining. The pilot has flown 210 total hours, 12 of them on type, and has not landed in gusty conditions for four months. There is no other suitable runway within 25 minutes' flying time.
1. Calculate the steady and gust crosswind components and determine whether the approach should be continued.
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The angle between runway heading (270°) and wind direction (320°) is 50°. Crosswind component = wind speed × sin 50° = 0.766 × speed.
Steady component: 18 × 0.766 = 13.8 kt - below the 17 kt demonstrated limit. Gust component: 27 × 0.766 = 20.7 kt - above the demonstrated limit.
'Maximum demonstrated' is not a hard limitation in the legal sense, but it is the only crosswind value for which the manufacturer has shown controllability, and the manual gives no gust allowance. A gust to 20.7 kt exceeds it by roughly 3.7 kt (about 22%). Because the gust is transient the aircraft may handle it, but the pilot cannot rely on demonstrated controllability at that value. The decision should weigh: (a) the exceedance is real and not marginal; (b) the pilot's recency in gusty crosswinds is poor (four months, 12 h on type); (c) no alternate within 25 minutes. A defensible judgement is to discontinue the approach, hold or divert to the distant alternate, and treat fuel (90 min) as adequate for that diversion. Continuing would require a strong justification that the pilot does not currently have the recency to support.
2. Explain how gusting wind affects the landing distance and the pilot's margin on this runway.
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The published 640 m landing distance is for steady conditions at maximum landing weight on a dry runway and includes no gust factor. A gust increases indicated airspeed at the moment of crossing the threshold if the pilot holds a constant target speed, so the aircraft touches down faster and floats. Landing distance varies roughly with the square of touchdown speed, so a few knots of excess speed produces a disproportionate increase. Typical operating practice adds half the gust increment to the approach speed, which raises the touchdown speed and lengthens the ground roll. On a 1,200 m strip with 640 m book figure, the nominal margin is 560 m, which sounds generous, but it must absorb: float from excess speed, delayed braking, and any directional work in crosswind. The gust also makes the headwind component variable, so the pilot cannot count on the wind to shorten the roll. The safe conclusion is that the effective margin is smaller than the arithmetic suggests and the gusting crosswind, not the runway length, is the binding constraint.
3. Identify the human factors and regulatory considerations that should shape the go/no-go decision.
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Human factors: the pilot is 40 minutes into the flight, so fatigue is low, but recency in gusty crosswinds is poor (four months) and type experience is low (12 h of 210 total). Low recency plus a high-workload crosswind landing raises the risk of a late go-around, over-correction or a hard landing. The 'no alternate within 25 minutes' pressure is a classic continuation bias - the pilot may press on because diverting is inconvenient rather than because it is safe. A structured decision (for example, a personal minimums checklist or the IMSAFE/PAVE frameworks) should be applied before the approach, not during it.
Regulatory: the aircraft must be operated within its flight manual limitations; 'maximum demonstrated' is not a limitation, but operating beyond it without manufacturer data is hard to defend. The pilot must be able to comply with the applicable visual approach and landing requirements and must not land with insufficient fuel; 90 minutes remaining is adequate for a diversion. The pilot in command holds final authority and responsibility, so the decision and its rationale should be recorded. If the approach is continued, a firm go-around trigger (for example, exceeding a stated crosswind or touchdown point) should be set before short final.