A method for detecting a change in fly-height comprises measuring motor
currents at various radii at a regular interval to determine the head
drag. If any of the head drags at the various radii are greater than a
threshold value, it is determined that a decrease in fly-height has
occurred. If the disk drive has a head cleaner, a head cleaning is
initiated to correct the fly-height change. If no head cleaning is
necessary, a general error signal may be generated to indicate potential
drive failure.