Severity Levels

Severity levels are defined by the difference in elevation across the fault and the associated decrease in ride quality and safety as severity increases.  Criteria for runway/taxiway pavement is more stringent than for aprons.

L - Runways/Taxiways < ¼ in. (< 6mm)
     Aprons 1/8 in to ½ in.

 M – Runways/Taxiways ¼ to ½ in.  (6  to 13 mm)
        Aprons ½ to 1 in. (13 to 25 mm)

 H – Runways/Taxiways > ½ in. (13 mm)
       Aprons > 1 in. (25 mm)