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I'd like to know how safe the Boeing 737-800 is during takeoff and landing when it's windy. What are the maximum wind speeds for cases of tail, head and cross winds?

EDIT

I've found this resource http://www.b737.org.uk/limitations.htm#Wind_Limits, but I'm quite unable to understand the data:

enter image description here

According to the table (which only shows x-wind data), the max wind speed depends on the so called "braking action", but I don't know what exactly is nor what it depends on.

EDIT 2

The same resource points out the max tailwind speed, as well as other info: enter image description here

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2 Answers 2

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As your source shows, the maximum tail wind is fixed and fairly simple.

Getting slightly more complex, there is technically no maximum headwind I'm aware of, although most airports will close when the wind gets much above 50 knots, and even with the wind coming almost straight down the runway, you still get some crosswind component, which factors in. Expect to see many pilots divert in winds much above 40 knots even if the airport is open, especially if gusting to above 50.

Crosswinds are a little different as they depend on the braking action - basically how grippy the runway is. Simplified, you can think of it as a scale from dry weather, through slightly and very wet, then slush and ice. The grippier the runway, the more the tyres will grip and the higher crosswind the aircraft can deal with. The higher numbers in the chart you show are for a dry runway (good on your chart) the lower numbers for wet or icy (poor on your chart) runways.

Although it's written in terms of 'braking action', it's really a measure of grippiness, and it's important both when braking, but also for the ability of the tyres to prevent the aircraft sliding laterally off the runway. This job doesn't solely come down to the tyres, but they're part of it. This is also a large part of the reason why landings and takeoff have different maximum crosswinds on some aircraft.

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If we are talking about 737 then there is maximum headwind. Landing speed for 737 is Vref + 1/2 headwind and cannot exceed Vref + 20. That means that maximum headwind component can not be more than 40knot

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  • $\begingroup$ .⁠.⁠.⁠sou⁠rce⁠? $\endgroup$
    – Vikki
    Commented Mar 28, 2021 at 1:13
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    $\begingroup$ The posted information here is not correct. The ADDITIVE doesn't go above +20 knots; that computation process doesn't drive a max headwind component. $\endgroup$
    – Ralph J ♦
    Commented Mar 28, 2021 at 2:29
  • $\begingroup$ @RalphJ, maybe i'm reading it wrong. Does it mean that you can't do landing with more than 40knots? Or it means that you can do more than 40 knots, but the additive component is limited to 20 knots? $\endgroup$
    – Maxim Cheusov
    Commented Mar 29, 2021 at 2:37
  • $\begingroup$ The latter. The additive is limited to no more than +20, even if the computation would give a higher number. For instance, a headwind of 22 gusting to 32... the additive would compute out as 11 (half the steady value of 22) plus 10 (the gust increment) equals +21. But you'd only add +20. Don't believe Boeing publishes a "max headwind" limitation the way they publish the max tailwind operating limitation. $\endgroup$
    – Ralph J ♦
    Commented Mar 29, 2021 at 3:11

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