Diversion Spacing
How PlaneWX scans your route for runway-suitable diversion options and surfaces long gaps on the route map.
What Is Diversion Spacing?
Diversion spacing answers a practical question: along your planned route, how far are you from a runway that meets your aircraft's minimum requirements? PlaneWX samples the route corridor, estimates time to the nearest suitable airport at your cruise speed, and flags segments where that time is unusually long.
This is a structural route-planning check, not a weather NO-GO. A long diversion gap does not automatically lower your WX Score — but it is worth knowing before you commit, especially on overwater, desert, or international segments where suitable fields are sparse.
How the Scan Works
Corridor width
Airports within 60 NM of your route polyline are considered. The scan uses your aircraft profile: minimum runway length and paved-only setting when configured.
Sampling
The route is sampled every 10 NM. At each point, PlaneWX finds the nearest runway-suitable airport in the corridor and converts distance to minutes at your planned ground speed.
Gap thresholds
- Gap spike (≥ 20 min) — Contiguous segments where time to the nearest suitable runway exceeds 20 minutes. Shown as purple hazard lines on the route map.
- Elevated (≥ 8 min) — No full spike, but spacing is tighter than ideal; may trigger a briefing callout.
Route Map Layers
In Detailed briefing view, open the route map and use the layer toggles:
Diversion gaps
Purple segments along the route where spacing exceeds the gap spike threshold. Click a segment for distance along route, span length, and peak minutes to nearest suitable runway.
Diversion airports
Violet markers for practical nearest airports along flagged segments. Labels prefer major or scheduled-service fields when fly times are comparable — not just the closest coordinate in the database.
Map labels use a wider 150 NM search from gap points so practical alternates (e.g. a regional jetport vs. a nearby grass strip) appear on the map even when they sit outside the strict 60 NM corridor used for spacing math.
Briefing Callout
When spacing is structurally noteworthy — gap spikes, elevated max spacing, or no suitable airports in the corridor — a callout appears in your Detailed briefing. Grok may also mention diversion spacing in the En Route or Gotchas sections using the same server-computed facts.
If convective or other hazardous weather overlaps a gap segment, shadow scoring may increase workload outlook and cap compound risk — reduced contingency when weather and sparse divert options align.
What v1 Does Not Include
- •Fuel or endurance — spacing is time-to-runway, not whether you can reach an alternate on remaining fuel
- •Customs or international entry — any suitable runway in the database counts; border and clearance rules are your call
- •Additional METAR fetches for diversion markers — shows cached METAR when available, but does not fetch new weather data specifically for diversion airports; always verify full weather at alternates separately
- •Services or lighting — no FBO, fuel, or night-ops filtering beyond runway length and surface type
Important Notes
- Database coverage varies. Remote strips and some international fields may be missing or misclassified. Always cross-check with current charts and NOTAMs.
- Small ICAO codes are real. Codes like MM50 in Mexico are valid OurAirports identifiers for small strips — PlaneWX may show a larger practical alternate nearby on the map instead.
- Dense domestic routes often show nothing. A short hop over populated terrain with many suitable airports (e.g. 66TE→KVBT) typically has no gap spikes — that is expected.
- Planning aid only. Diversion spacing supports situational awareness; your PIC divert decision still depends on weather, fuel, aircraft state, and ATC.