Modified criteria for runway roughness are needed for any functional evaluation, especially, when dealing with modern fighter jets. To this end, a comprehensive pilot attitude survey was conducted in Israel in order to obtain reliable subjective runway roughness ratings. These rating were to provide predicted roughness index values using objective measurements. This was done through the use of a newly adopted geometric numeric, capable of detecting critical rough segments along the entire runway. Additionally, some braking distance tests combined with pilot questionnaires were included in the study and found to be important inputs for the development of the required criteria, along with various TAXI computer runs carried out on some predefined theoretical surfaces. All of the above led to the final criteria for the "should be repaired level", the "must be repaired level" and the structural safety level for the fighters' landing gears. Finally, these criteria were examined against the limited values of the various accelerations discussed (i.e. PSA, CGA or MGA) and found to be solid ones.
Abstract