US Patent 7633696 Fly height calibration for read/write heads

A fly height controller that controls fly height of a read/write head relative to a rotating data storage disk is calibrated. A heater signal is applied to a heater element to heat the head. The level of a write current that is conducted through the head is increased until the head contacts the disk. The fly height controller is calibrated based on at least a first level of the heater signal and a first level of the write current when the head contacts the disk.