When LNAV is used to program a route within Australia between two waypoints, the database track that the aircraft will follow is:

• A. A great circle
• B. A rhumb line
• C. A straight line on a Mercator projection
• D. A direct magnetic bearing

Answer: (A)

LNAV follows the computed path between two waypoints that is defined in the navigation database as a great-circle track—the shortest line between the two points on the Earth's surface. This means the aircraft flies along that curved arc on a globe, even though on some flat map projections it can look like a curved or odd shape. A rhumb line (constant bearing) would appear as a straight line on a Mercator chart, but LNAV does not fly a constant bearing; it follows the great-circle arc to minimize distance and fuel. A direct magnetic bearing would imply locking a single magnetic heading along the leg, which isn’t how RNAV/LNAV routes are constructed, since magnetic variation changes along the route. So, the database track LNAV uses between two waypoints is the great-circle track.