The Navitimer circular rule , referred to by Breitling as a `` navigation computer '' , featured airspeed , rate\/time of climb\/descent , flight time , distance , and fuel consumption functions , as well as kilometerâ `` nautical mile and gallonâ `` liter fuel amount conversion functions . The Navitimer circular rule , referred to by Breitling as a `` navigation computer '' , featured airspeed , rate\/time of climb\/descent , flight time , distance , and fuel consumption functions , as well as kilometerâ '' nautical mile and gallonâ '' liter fuel amount conversion functions .