An apparatus for setting a minimum value of a value of a shock absorber dimension of a shock absorber of an aircraft landing gear, the shock absorber dimension being indicative of an extension of the shock absorber, wherein a measured shock absorber dimension value being below the minimum value indicates that the landing gear requires servicing and a measured shock absorber dimension value being above the minimum value indicates that the landing gear does not require servicing, the apparatus comprising: a processor configured to: identify a respective range of values relating to each of a plurality of operating characteristics under which the shock absorber may operate; identify a respective probability distribution of values for each of the operating characteristics within the identified ranges; perform a generation process for generating a plurality of values of the shock absorber dimension by repeatedly: (i) selecting, as input into a computer-implemented model for determining a value of the shock absorber dimension, a value of each of the operating characteristics based on the respective probability distributions; and (ii) determining a given value of the shock absorber dimension using the selected values and the computer-implemented model; and set the minimum value based on the generated plurality of shock absorber dimension values. a processor configured to: identify a respective range of values relating to each of a plurality of operating characteristics under which the shock absorber may operate; identify a respective probability distribution of values for each of the operating characteristics within the identified ranges; perform a generation process for generating a plurality of values of the shock absorber dimension by repeatedly: (i) selecting, as input into a computer-implemented model for determining a value of the shock absorber dimension, a value of each of the operating characteristics based on the respective probability distributions; and (ii) determining a given value of the shock absorber dimension using the selected values and the computer-implemented model; and set the minimum value based on the generated plurality of shock absorber dimension values. identify a respective range of values relating to each of a plurality of operating characteristics under which the shock absorber may operate; identify a respective probability distribution of values for each of the operating characteristics within the identified ranges; perform a generation process for generating a plurality of values of the shock absorber dimension by repeatedly: (i) selecting, as input into a computer-implemented model for determining a value of the shock absorber dimension, a value of each of the operating characteristics based on the respective probability distributions; and (ii) determining a given value of the shock absorber dimension using the selected values and the computer-implemented model; and (i) selecting, as input into a computer-implemented model for determining a value of the shock absorber dimension, a value of each of the operating characteristics based on the respective probability distributions; and (ii) determining a given value of the shock absorber dimension using the selected values and the computer-implemented model; and set the minimum value based on the generated plurality of shock absorber dimension values.