"INTRODUCTION This Data Item is the second of a series of examples of the application of a method for representing ?C and@ if necessary@ relating ?C the braking performances of aircraft and ground-test machines in wet conditions. The method@ which is given in Reference 4@ is essentially statistical and implies that there is a clearly-defined level of probability that can be deduced from test runs of an aircraft (or ground-test machine) in a given set of wetness conditions on a particular runway. If the runway macro-texture depth is known@ then the parameter that defines the variation of effective coefficient of braking friction in the given conditions can be readily calculated from a pre-determined Friction Data Base. The concept of a Friction Data Base is explained in Reference 4. The Item uses test data collected from a short trial on a small combat aircraft to illustrate the way in which a very limited amount of information can be used to establish a Friction Data Base. For this aircraft the data were limited in so far as the tests were made on a single runway and the measured quantities were ""brakes-on"" speed and stopping distance. The background to those tests is described in Section 3. The methods of analysis are summarised and results are presented in Section 4. The first example@ for an aircraft where an extensive set of test data is available@ is given in Reference 5. An example of the application of the method to ground-test machine data is given in Reference 6. Many other examples are considered in Reference 3. If the method of Reference 4 is to be used to relate the braking performances of a given combination of aircraft and ground-test machine@ the procedure is comprised of two distinct phases. The first is the establishment of separate Friction Data Bases for the aircraft and for the ground-test machine. The second is the prediction of operational braking performance of the aircraft using day-to-day measurements from the ground-test machine."