Originally Posted by
john_tullamarine
However, the Vmcg concern with crosswind generally is not a problem in routine line operations. It presents in very limited circumstances and only for a quite small range of speed in excess of Vmcg - the centreline deviation characteristic curve rapidly moves out of the problem area .. which is why we don't fuss too much about the topic in routine operations .
Thanks. I guess it would take engineering information and analysis to know how much of a range in excess of the published Vmcg that this would extend. Something that would be very interesting to see.
Originally Posted by
john_tullamarine
This information ... has nothing to do with an engine failure scenario which does not consider crosswinds or contamination in terms of directional control.
Are you sure of that ? Perhaps you can cite appropriate references to support the contention ?
The only thing I can find is FAA AC25-7B FLIGHT TEST GUIDE FOR CERTIFICATION OF TRANSPORT CATEGORY AIRPLANES. In the explanation below, no mention is made about an engine inoperative scenario.
Section 7. Ground Handling Characteristics
(a) Landplanes.
1 There must be a 90-degree crosswind component established that is
shown to be safe for takeoff and landing on dry runways.
2 The airplane must exhibit satisfactory controllability and handling
characteristics in 90-degree crosswinds at any ground speed at which the airplane is expected to
operate.
(c) Crosswind Demonstration. A 90-degree crosswind component at 10 meters
(as required by § 25.21(f)) of at least 20 knots or 0.2 VSR0 (where VSR0 is for the maximum
design landing weight), whichever is greater, except that it need not exceed 25 knots, must be
demonstrated during type certification tests. There are two results possible:
1 A crosswind component value may be established that meets the
minimum requirements but is not considered to be a limiting value for airplane handling characteristics. This “demonstrated” value should be included as information in the AFM.
2 A crosswind component value may be established that is considered to be
a maximum limiting value up to which it is safe to operate for takeoff and landing. This “limiting” value should be shown in the operating limitations section of the AFM.
(2) Procedures.
(a) Configuration. These tests should be conducted in the following
configurations:
1 At light weight and aft c.g. (This is desirable; however, flexibility should
be permitted.)
2 Normal takeoff and landing flap configurations using the recommended
procedures.
3 Normal usage of thrust reversers. Particular attention should be paid to
any degradation of rudder effectiveness due to thrust reverser airflow effects.
4 Yaw dampers/turn coordinator On, or Off, whichever is applicable.
(b) Test Procedure and Data. Three takeoffs and three landings, with at least one landing to a full stop, should be conducted in a 90-degree crosswind component of at least 20 knots or 0.2 VSR0, whichever is greater, except that for airplanes whose certification basis includes amendment 25-42, it need not exceed 25 knots. For each test condition, a qualitative
evaluation by the pilot of airplane control capability, forces, airplane dynamic reaction in gusty crosswinds (if available), and general handling characteristics should be conducted. The airplane should be satisfactorily controllable without requiring exceptional piloting skill or strength. Wind data from an inertial navigation system (INS), tower, or portable ground
recording station should be corrected to a 90-degree crosswind component and to a height of 10 meters.
For my aircraft, the AFM states "M A X I M U M C R O S S W I N D
The maximum crosswind component for takeoff and landing is 30 knots
reported wind at a 10-meter (32.8-foot) height. This component is
not considered to be limiting on a dry runway with all engines
operating."