An apparatus, method and computer program product for a hard disk drive (10) defect detection system. In one embodiment, a method of detecting defects on the surface of a disk (12) having a plurality of tracks (t n ) is recited. The method comprises reading, one or more times, the servo bits for a plurality of sectors (i) and determining a burst measure for at least one sector, where the burst measure is a function of the burst signals for the sector. This method further comprises determining a reference value, where the reference value is a function of the burst signals of the plurality of sectors, and comparing the burst measure of at least one sector to the reference value to identify a potential defect. In one embodiment, a sector is mapped as defective where its burst measure differs from the reference value by at least 5 percent.