LNAV Segments Calculator

Divide long-distance orthodromic routes into constant-heading loxodromic segments. Simulates how FMS/LNAV systems approximate great circle routes.

Route

From

KJFK

40.6394, -73.7793

RJAA

35.7647, 140.3860

Number of Segments: 10

How It Works

Modern Flight Management Systems (FMS) approximate the shortest great circle route by dividing it into constant-heading segments. This calculator demonstrates this process:

Great Circle: The shortest distance between two points (orthodromic route)
Waypoints: Places N waypoints evenly along the great circle
Segments: Flies constant heading (rhumb line) between each waypoint
Total Distance: Sum of all segment distances (longer than great circle)

Key Insight: With fewer segments, each rhumb line deviates more from the great circle, increasing total distance. More segments = better approximation = closer to the shortest path.

Example: For a 3000 NM route:
• 1 segment (direct rhumb line): ~3090 NM (+3%)
• 10 segments (Pan Am era): ~3008 NM (+0.3%)
• 100 segments (modern FMS): ~3000.5 NM (+0.02%)