Disk drive actuator arm assembly having one or more slotted actuator arms

A disk drive, includes a disk and a head stack assembly for reading and writing to the disk. The head stack assembly includes a body portion defining a through bore that defines a pivot axis; an actuator arm cantilevered from the body portion, the actuator arm defining a thickness, the actuator arm defining at least one through slot in the thickness thereof through which air can flow, each through slot defining a slot surface that is generally perpendicular to the pivot axis; a coil portion cantilevered from the body portion in an opposite direction from the actuator arm, and a head gimbal assembly coupled to the actuator arm.