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Aircraft Performance, Tailwind

Crosswind Challenges

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. In this section 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 as the rules require that of the pilot in command.

The effect 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.

Some pilots see it as a challenge when the wind changes to a good crosswind, and it is. Doing it right takes hours of practice combined with a good explanation of how it is done, so continue reading.

Crosswind landings

There are three situations when there is no crosswind at all: with no wind and with an exact head or tailwind. Then and only then, the crosswind will be no factor. During take-off and landing crosswinds can be difficult to handle and during flight training the new pilot must learn this properly and be comfortable with them.

Crosswind calculations

To calculate the crosswinds for take-off, landing and enroute see the image for the standard crosswind chart or just use the calculator below.

Runway Heading (e.g. 240)
Wind Direction (e.g. 120)
Wind Speed
The runway crosswind is Knots
Crosswind ChartCrosswind Chart
Crosswind Chart

Handling crosswinds

Handling a crosswind during landing can be quite the task, especially for new pilots. Basically there are two methods for approaching a runway with a crosswind: Crab into the wind and the Wing down/slip method.

Crab method (preferred)

Crab Method Landing

I prefer the crab method, it's a whole lot easier to do but more difficult to master. Just fly to the runway with the nose into the wind as always. If this can not be done you know its time to divert to a more favorable runway/airport.

In this sutuation the aircraft does not slip (important when fuel levels are getting low), all available stick/yoke control for counteracting turbulence is available and you and the passengers do not lean sideways. Everybody sits comfortable.

The difficult part is during the landing touchdown: you must line the aircraft up with the runway with the rudder and bank into the wind (in that order and thus compensating for the crosswind) moments before touchdown, while the speed reduces. At this point the aircraft changes to the wingdown situation and at almost the same time touchdown is accomplished. Remember to keep the stick/yoke into the wind during roll out and taxi.
Maintain some power during touchdown as the wingdown method introduces more drag.

Wingdown / sideslip

Sideslip Method Landing

The wing down/slip method requires the pilot to fly the aircraft lined up with the runway and banked into the wind when turning on final, at this point the aircraft slips and consequently stall speed is higher. Some find this the easy way. But if turbulence is encountered, stick or yoke control could possibly be not enough to counter it and a stable approach can not be maintained.

When this happens you will be blown away from the center line and might have to abort the landing. You and the passengers lean toward the low side (this could not be comfortable for them) and so does the fuel in the tanks. Especially a problem if the fuel level in the tank is low, where the fuel is likely to be pushed away from the tank outlet thereby possibly starving the engine. With full tanks the fuel could be forced out of the vents draining overboard.
The landing procedure is the same as with the crab method.

Possible spin

One more reason for NOT using the wingdown method is that the aircraft is slipping and stall speed is increased. Guess what happens if you enter a stall (due to turbulence) in a slipping aircraft... An immediate spin to the low wing is the result. Now try to recover from that at 400 ft AGL or lower on final approach to the runway.

Reduced headwind

Crosswinds reduce your headwind component (only when the crosswind is more or less from up front). Basically if the crosswind is 30 degrees off the runway heading it reduces the headwind by 15%. At 45 degrees it will be 30% less headwind (at 90 degrees none at all!). Something to keep in mind when heading for short runways.

Crosswind Take-offs

This is the same procedure as with a landing, but only in reverse. The procedure is to line-up with the runway and keep the stick/yoke fully into the wind. Slowly add full power while keeping the aircraft aligned on the centerline with the rudder. Hold the aircraft on the runway somewhat longer than normal and lift-off.

The aircraft will lift-off with the downwind wing higher than the upwind wing in a wing down attitude. When the wheels are off the runway reposition into the crab attitude and climb out keeping the aircraft aligned with the runway centerline. Remember that winds increase and veers some degrees when climbing so you need to compensate for that too.

Written by EAI.

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