TP 13579 PROCEEDINGS of the 2nd International Meeting ... - UQAC

IMAPCR ’99
118. Issues related to braking include:
• shortage of available data, e.g., minimal data for very wet or flooded surfaces, reasonable
quantity of data available for snow, some data available for icy surfaces;
• ESDU wet statistical method can be extended to contaminated surfaces;
• low speed (less than 50 kt) flooded testing is helpful;
• controllability is important; high data accuracy is not necessary.
119. Landing braking reports may be summarized as follows:
• ESDU statistical methods are useful;
• drag and friction need to be segregated;
• banding of values leads to accuracy;
• operational flexibility is needed;
• speed and accuracy of measurements are important;
• pragmatism is essential.
120. Mr. Skillen concluded by saying that calculation of effects is at hand. He stressed that
operational considerations are important and must not be subordinated to technical purity.
121. A participant agreed that focus on pragmatism, as suggested by Mr. Skillen, was indeed
important and highly desirable.
122. The following comments and suggestions were offered from the floor:
• what is needed is good ground sample data that a pilot can use;
• the effects of crosswinds should be in the operating manual;
• wet runways and crosswinds do not make a good combination;
• the flight manual is not wrong – even if the AMJ is wrong;
• the assumption of uniform depth of snow/ice is not realistic.
123. When asked whether a new approval of AMJ was required, Mr. Skillen replied that it was
not. The data in the AFM is different from that in the AMJ. Authorities accept the AFM
instructions.
124. Mr. Skillen agreed that the contaminant thickness on the runway surface is not uniform. He
said, however, that one starts with the assumption of uniform thickness and then applies
correction factors.
125. A comment was made about adjustments to Vmcg for slippery conditions and crosswinds.
Mr. Skillen responded that determining Vmcg is tricky and that manufacturers resolve this by
adding 6kt in the calculation. He also raised concerns about the assumption of using V1=VR
to balance the field calculation.
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