What is the strongest wind in which passenger jets can fly?
There is no single maximum wind limit as it depends on wind direction and phase of flight. A crosswind above about 40 mph and a tailwind above 10 mph can start to cause problems and prevent commercial jets from taking off and landing.
It can sometimes be too windy to take off or land. Limitations are in place for the safety of passengers and crew.
Airplane and Wind – An Overview
In aviation, speed is measured in knots (nautical miles per hour). This is converted to miles per hour (mph) by multiplying it by 1.15.
Maximum wind limits for commercial aircraft depend on the aircraft, the airport, and the direction of the wind relative to the direction of takeoff or landing.
For takeoff and landing, the aircraft has different limitations, and these are further divided into dry, wet, or contaminated runway limitations. A contaminated track is an area where there is snow, ice or standing water on the track.
Maximum aircraft wind limits are divided into:
- Crosswind component – the lateral element of the wind
- Headwind – amount of wind from the front of the aircraft
- Tailwind – amount of wind behind the aircraft
- Total wind – total wind speed
Aircraft want to take off and land into a headwind because it reduces the distance they need to take off or the distance needed to bring the aircraft to a stop. If an airplane is stationary on the runway and has a headwind component of 20 knots, that is 20 knots of air flowing over the wing and therefore giving the airplane a speed of 20 knots, even if it does not move. If it has a takeoff speed of 140 knots, the ground speed of the plane would only need 120 knots to take off because it already has 20 knots of speed against the wind.
Typically, commercial aircraft demonstrate an ability to land with some crosswind at the aircraft certification stage. This demonstrated limit is not a maximum limit, but it is the figure that most operators (airlines) will choose to use as a limit – it is unwise to have an uncapped figure. Therefore, the numbers provided below for the B737-800 are typical of those dictated by an operator, not the manufacturer.
On a dry runway, a Boeing 737-800 has a maximum allowable crosswind component of approximately 33 knots. For a take-off on a wet runway, it’s about 27 knots. The actual figure may be slightly higher or lower, as the airline can choose to set their own more restrictive value if they wish. If the crosswind component were greater than this, the aircraft might have the option of choosing another runway with more wind exposure, but in the case of a single-runway airport, it would not be able to take off.
There is no headwind limit for most commercial aircraft for takeoff, and therefore there is no maximum overall limit for takeoff (or landing). If there was a 100 mph wind, which was entirely a headwind component, in theory the plane would not be prevented from taking off. However, the reality is that there are wind limits to opening and closing the aircraft doors (around 45 knots) and no pilot would attempt to taxi and take off in such conditions. The airport would have closed in such circumstances anyway!
Downwind vs Heading
The maximum allowed tailwind value is generally between 10 and 15 knots. Tailwinds are easy to avoid at most airports, like if you just take off the other way, the headwind has now become a tailwind. Tailwind has the opposite effects of a headwind, increasing the runway distance needed to take off and land.
However, at some airfields it is actually better to accept a tailwind on one runway rather than a headwind on another due to potential terrain problems. Florence (FLR) is a good example. It’s actually better to accept a little tailwind on Runway 23 than a headwind on RWY 05 because of the very large hill/mountain very close to RWY05. If you were to lose an engine, you still need to be able to meet a guaranteed climb grade to get you above the terrain on the RWY 05, which can mean you’re very weight limited even with a headwind. . You can actually increase your maximum takeoff weight even by accepting a tailwind on the RWY 23.
On a dry runway, the Boeing 737-800’s crosswind limitation is the same as on takeoff, 33 knots. On a wet track, this reduces to a maximum of 30 knots.
The maximum tailwind component for takeoff and landing is usually between 10 and 15 knots, but the actual figure that can be used may be limited by runway length, aircraft weight, etc.
In the case of a contaminated runway, the maximum allowable crosswind and tailwind limits decrease, depending on the type and depth of the contaminant. Most airlines do not allow a downwind takeoff from a contaminated runway.
Some aircraft specify maximum taxi limits. For example, on the Boeing 737, the maximum taxiing speed is 65 knots.
There are limits on when the cargo and passenger doors can be opened. If the wind is above approximately 45 knots, it is not considered safe to open the doors.
Other things that affect the maximum wind allowed:
- The airline could impose stricter restrictions than manufacturing. Therefore, one Boeing 737-800 airline may have different limits than another airline operating the same aircraft.
- Drivers have different limits. Captains can generally operate the aircraft up to specified maximum limits, but senior and junior co-pilots will have more restrictive limits. The captain will make the landing if he exceeds his limits.
- Some airports impose restrictions on wind limits. For example, at London City Airport, the maximum crosswind limit is 25 knots, while some of the aircraft operating there have a dry runway limit of 38 knots for take-off and landing. This is because it is narrower and shorter than other airports.
- Aircraft design. An airplane with a large vertical stabilizer (the large tail fin) will be more affected by a crosswind than one with a smaller one. A plane with wings is also more likely to be affected by crosswinds.
The airport itself may limit the maximum permitted wind limits. For example, at London City Airport (LCY), the maximum crosswind limit is 25 knots for all aircraft because the runway is only 30m wide (compared to a standard width of 45m or sometimes even 60 m at larger airfields).
Aircraft type and aerodynamics
Maximum wind limits between aircraft differ due to differences in aerodynamics and handling. Generally speaking, the taller the vertical stabilizer is relative to the rest of the aircraft, the more the aircraft will be affected by a crosswind. Larger aircraft compensate for this by having larger control surfaces, thus giving pilots greater control authority. If you take the Boeing 777 for example, its crosswind limit for landing on a dry runway is 40 knots – more than a Boeing 737.
Some of the same aircraft types even differ due to their configuration. For example, a standard A320 has a higher crosswind limit than an A320 with Sharklets (of Airbus version of winglets), because the Sharklets are an additional vertical surface on which the wind can act.