ARP Centroid Calculator
Compute a proposed Airport Reference Point as the length-weighted average of runway centerline midpoints — the geometric center of all usable runways per AC 150/5300-13B ¶1.8.1 (computation method per legacy AC 150/5300-13A ¶107). Enter both ends of each runway, or import them from an airport.
Runway
End 1 Lat (DD)
End 1 Lon (DD)
End 2 Lat (DD)
End 2 Lon (DD)
Computed ARP
Latitude
Longitude
Controlling standard
AC 150/5300-13B ¶1.8.1 (computation method per legacy AC 150/5300-13A ¶107)
Assumptions
- Spherical-earth model — runway lengths computed by the haversine great-circle formula (R = 6,371 km), reported in US survey feet.
- Each runway contributes its centerline midpoint (arithmetic mean of its two end coordinates).
- Midpoints are averaged weighted by runway length; relative weights are scale-free, so the sphere radius cancels out of the result.
Logic — contributing runways
Warnings
- Computed value — verify against survey-grade data before official or regulatory use. This is a planning estimate, not a substitute for a stamped survey or the published FAA ARP.
Data vintage
N/A — computed from user-supplied runway coordinates, not a dated data edition or cycle.
Cross-tool