A tracking base assembly for an aircraft seat includes base rails mounted to floor tracks in an aircraft cabin by floor track fittings in fixed positions, the base rails connected by a tracking member for providing longitudinal tracking while minimizing added height. The base rails include tracking slots extending longitudinally, and the tracking member includes tracking elements translatable forward and backward along the tracking slots, allowing an aircraft seat mounted to the tracking member to translate forward from a retracted configuration into an extended or berthing configuration (and backward to the retracted configuration). The tracking member includes a locking mechanism for locking the tracking member and seat in intermediate positions within the tracking slots. The tracking slots may be oriented slightly downward from the horizontal to allow for gravity-assisted tracking or to counteract the nose-up flight angles associated with cruising altitude, providing for easier seat tracking.