The certification requirements (AFM) for cross wind landings are given in
CS 25 Large Aircraft AMC 25.1581 6 3 (G) (about page 648)
As above, the manufacturer’s tests determine either the maximum demonstrated crosswind - not limiting (but unknown handling qualities in higher crosswinds), or where determined a limiting value, which is published in the limitations section of the AFM.
Generally, the certification tests are conducted on dry runways. Tests could be conducted on different runway surfaces (friction), but this creates problems in relating the test data with the vast range of conditions likely to be encountered in daily operations.
The effect of reduced runway friction can be calculated, but again crews’ rarely have runway condition data with sufficient accuracy. As an example, see
MTED Approach and Landing slide 26, which shows a range of friction values for a grooved / non-grooved wet runway. In addition to this, the calculations (and reports to the crew) would have to consider runway texture, contaminant type and depth, amongst many other variables.
An example of the complexity (although a good solution) is given in
Transport Canada AIM/AIR, see Table 3 which links crosswind with friction via CRFI, which IIRC, is not used outside Canada.
Thus, a general ‘operational’ solution is often used and the responsibility for this is with the operator / crew. Be very cautious of a crosswind on wet runway; heed the variability in wind reporting – see refs below.
Notes on crosswind landings from Boeing presentation:-
“Boeing publishes takeoff and landing crosswind guidelines in the Flight Crew Training Manuals
– Derived from analysis and piloted simulations
– Based on steady winds
– Function of runway condition
– Accounts for asymmetric reverse thrust
– Provides guidance on technique (side slip, crab)”
Runway Condition / Crosswind - Kts
Dry 40
Wet 25
Standing Water/Slush 15
Snow – No Melting 20
Ice – No Melting 15
(IMHO rather optimistic values)
See
ALAR Tool Kit Guidance Chap 8.7, also 8.5, and 8.6
IIRC this info is in general that used by Airbus, but their advice is also in
Landing Techniques – Crosswind Landings.
Refs:
Crosswind - positon paper.
Crosswind Certification - How does it affect you?
Safety aspects of aircraft operations in crosswind.
Safety aspects of aircraft performance on wet and contaminated runways.
STAR 004