Crosswind Chart

Taking off into the wind

Most aircraft accidents occur during the take-off and landing phase of the flight. Collisions with obstacles during climb out, runway overruns on landing occur every now and then. On this part of the site we will take a look at the various factors contributing to the performance of the aircraft in this part of the flight. Hopefully we help the pilot ensuring safe operation during these phases of the flight as the rules require that of the pilot in command.

The effect of wind has on our aircraft is something we can influence to some extend. We can choose runways with the greatest headwind component (when the airport has multiple) and use the wind on our tails when flying to our destination. Wind speed and direction sometimes varies with altitude so that can be used too.

The last part of the flight can be the most demanding for the pilot, and during training he/she will spend a lot of time practicing these.

Headwinds & Tailwinds

Aircraft use the flow of wind over the wings to generate lift to be able to fly. A minimum amount is required to liftoff and usually the engine generates thrust to obtain this liftoff speed.

Headwind

By taking off into the wind (the wind will generate part of the required lift) the aircraft lifts off sooner and this will result in a lower ground speed and therefore a shorter take-off run for the aircraft to become airborne.

It is therefore recommended. Not only for safety reasons: a take-off that is abandoned will also use less runway to stop because ground speed is lower (check ASDA). Climbing into the wind will result in a steeper climb, perfect for clearing obstacles in your climb out path.

Landing into the wind has the same advantages, it uses less runway, ground speed is lower at touchdown (less wear and tear on the aircraft) and the runway is available sooner for the next aircraft when it gets a bit crowded.

A rule of thumb says that take-off and landing distances are reduced 1,5 % for each knot of headwind up to 20 knots.

Tailwind

Take-offs with a tailwind will result in the use of much more runway to get enough lift for flight (It takes distance to nullify the tailwind before any headwind is obtained for lift). Climb angle is also reduced. Think obstacles! A five knot tailwind increase take-off distance with 25% and a ten knot tailwind with 55%.

The same can be said about landing distances. Reasons for doing tailwind operations could be noise abatement procedures or commercial operations and in case of certain mountain airports where you land up slope and take-off down slope again.

Landing

Landing with a tailwind has another problem: you will approach the runway with a higher ground speed and this could lead the pilot into lowering his airspeed because he/she is accustomed to a lower ground speed. At this point a stall can happen. Just fly your usual indicated final approach speed and all is well.

Best thing to do is to avoid tailwinds during landing altogether, only if sufficient runway and pilot experience is available it can be done safely. Tailwinds do not lower the indicated airspeed or stall speed of the aircraft, they influence the groundspeed.

Turbulent Gusting Winds

On take-off with gusting winds it will be required that you keep the aircraft on the ground somewhat longer to provide a higher margin from the stall. During landing you must add half the gust factor to your final approach speed.

It is wise to do the same on take-off. Add half the gust factor to your normal lift-off speed, this should provide a safe margin. Keep in mind that because of these higher take-off and approach speeds more distance on the runway is required.