All inputs and outputs use the selected units. Internally calculations always run in NM and feet (the worksheet's reference units), so you can switch units at any time without losing your route.
Aircraft
Wind & Safety
5001,0001,5002,0002,500
Route — Waypointsno route
Round trip: requires altitude to safely return to departure throughout the flight (e.g. local soaring, racing tasks).
One way: only requires reaching the destination — useful for retrieves, ferry flights, and competition finishes at a different field.
Alternates Along Route—
Pick departure and destination airports first, then click Search to find landable alternates within the corridor.
Obstacles & Clearance
Applies to obstacles, terrain, and waypoint clearance calculations
Wind-Adjusted Glide Calculations
Speed to fly
Vbest + wind / 2
— kts
Headwind adjusted glide
(STF − wind) / STF × L/DSTF × SF
— : 1
Tailwind adjusted glide
(Vbest + wind) / Vbest × L/Dbest × SF
— : 1
Safe return reach
—
NM from departure
Forward glide reach
—
NM from current pos.
Destination status
—
enter flight details above
Airports along route — reach status
Reach status reflects whether you have enough altitude at your current position to safely glide to each airport (accounting for terrain, obstacles, wind, and the configured clearances). For alternates, the calculation uses the dedicated diversion-path terrain when available.
Route distance: —NM
Min alt at departure: —ft
Max safe distance from dep.: —NM
Flight Profile
Stay above both lines to keep the option of either continuing or returning at every point.
Required altitude jumps at each waypoint and obstacle to maintain clearance.
For round trips, the chart shows the full there-and-back profile, with the wind direction reversing on the return leg (separated by a dashed orange "TURN" marker).
Min alt to safely return to departure
Min alt to safely reach destination
Min alt to glide to intermediate WP
Current altitude
Glider (current position)
Obstacle
Endpoint airport
Main-route terrain (along planned path)
Diversion terrain (direct path to alternate)
Peak terrain in each 5-NM segment
Fill in glider, route waypoints, wind, and current altitude to see the flight profile chart.
1 NM = 6,076 ft ·
Obstacle clearance: 1,500 ft upwind · 500 ft downwind ·
Pattern alt = field elev + safety alt ·
Safety factor applied to both glide ratios
Route Map
Click an alternate marker to add it to the route
Layers: Toggle base maps (including FAA Sectional charts at zoom 8–11
for US airspace) and the OpenAIP aviation overlay (airports, airspaces, navaids)
using the layer control in the top-right corner of the map. FAA Terminal Area Charts
are available as a separate overlay at zoom 11–13 for major metros.
Route overlays: The direct line from departure to destination is shown dashed (when intermediate waypoints exist).
Altitude ticks appear every 5 NM along this line, labeled with the minimum altitude required at that point to reach destination —
green if you have enough altitude to be there now,
red if not.
A go-ahead point marker shows where your current altitude becomes insufficient.
Reachability heatmap legend:
Comfortable (current alt > required + 1,000 ft)
Tight (within 1,000 ft buffer)
Out of reach (current alt < required)
Each cell's required altitude is computed by walking the direct line from that cell to the nearest airport,
using real elevation data from Open-Elevation (cached locally after first fetch). Higher accuracy
uses a finer grid but takes longer to load the first time. Each region is labeled with the airport that's
easiest to reach from there (e.g., → KL08).