getting to grips with COLD WEATHER OPERATIONS 寒冷天气运行(57)

The wind component can be resolved into two directions: crosswind and head/ tail wind.
Similarly, thrust reverse component is resolved both in a component parallel to the
runway centerline, actually stopping the aircraft, and in a component perpendicular to the
runway. For the purpose of this example, let’s refer to it as .cross-reverse..

These two forces, crosswind and .cross-reverse. try to push the aircraft off the runway.
The cornering forces induced by the main wheel and the nose wheel must balance this
effect (as illustrated by Figure C15).

Figure C15
In such a situation, releasing the brakes would actually allow a greater cornering force to
be developed, thus, regaining aircraft directional control.
When using autobrake, LOW mode provides more cornering force than MED mode.

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C5 CROSSWIND

C5.1 Demonstrated crosswind
A demonstrated crosswind is given in the Aircraft Flight Manual (AFM). The words .demonstrated crosswind. have been intentionally selected to express that this is not necessarily the maximum crosswind that the aircraft is able to cope. It refers to the maximum crosswind that was experienced during the flight test campaign, and for which sufficient recorded data is available. It is also intentional that demonstrated crosswind is not given in the limitation section, but is in the performance section of the AFM.
Demonstration of crosswind capability is made on dry or wet runways and it is usually considered that the given figures are equally applicable to dry or wet runways.
In fact the information given by the AFM is an indication of what was experienced during certification flight tests to provide guidance to operators for establishing their own limitations. FAR/JAR 25 requires this information to be given.
The maximum crosswind for automatic landing is defined in the limitation section of the AFM. In this case, it has to be understood as a limitation. That is the limitation of the system.
C5.2 Effect of runway contamination
It is a matter of fact that a poor runway friction coefficient will affect both braking action and the capability to sustain high crosswind components. Airbus Industrie issued recommendations based on calculations and operational experience in order to develop guidelines on the maximum crosswind for such runway conditions. The FCOM - Special Operations - indicates the maximum recommended crosswinds related to estimated runway braking action. Figure C16
 below is an example provided in the A340 FCOM:
102

Figure C16
Caution:
Equivalent runway condition is only valid for maximum crosswind determination. Do not use this equivalence for takeoff or landing performance determination.
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CROSSWIND
Please, bear in mind:
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