General. Description. LXNAV. LX Flight Computer device comes packed with a GPS-Navigation System. LX GPS pdf manual download. Also for. GPS-Navigation System with Variometer LX System . The LXNAV system is designed for VFR use only as an aid to prudent navigation. carefully and are important for operating the LX system. The 57 mm diameter (2¼") LXNAV V5 vario unit is a modern designed variometer with its.