Airport, weather, and runway
Departure path Runway 21 · 70 KIAS · corridor ±0.5 NM
NWS, OpenStreetMap, and Open-Elevation receive the selected airport, map area, or corridor coordinates, plus ordinary request metadata such as your IP address. They do not receive source flight logs, aircraft weight, or the performance profile. The FAA runway snapshot is stored locally and does not receive your selection.
Climb path and sampled terrain
- Ground speed
- -
- Aircraft capability
- -
- Required gradient
- -
- Terrain corridor
- ±0.5 NM
- Minimum sampled separation
- -
Assumes the aircraft crosses the FAA departure end of runway (DER) 35 ft above DER elevation. Ground roll, liftoff, and the ability to reach 35 ft at the DER are not modeled. Sampled terrain is not obstacle or procedure clearance.
Terrain assumptions
Terrain is sampled within the selected corridor on each side of the intended ground track. The -15% margin is a scenario, not a safety factor.
Model evidence
Coverage and fit from this aircraft's recorded flights.
- Best-fit R2
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- Segments used
- -
- Windows used
- -
- DA coverage
- -
- Weight basis
- -
Climb rate by density altitude
Typical and P90 trends from eight accepted climb segments.
Model vs actual
Observed minus fitted trend.
Planning table
| Density altitude | Trend at gross | Scenario -15% | Observed median | Support |
|---|---|---|---|---|
| Loading this aircraft's model. | ||||
Source climb segments
No segments yet
Source climb segments
No segments yet
| # | Log | Start | Start DA | End DA | Delta | Duration | Avg fpm | Use |
|---|---|---|---|---|---|---|---|---|
| No segments yet. | ||||||||
Evidence only. Fit quality is in-sample.
How this model is built
GPS logs are filtered into steady climbs, adjusted for density altitude and estimated weight, then fit to a climb trend.
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Find steady climbs
Keep roughly one-minute climbs; reject gaps, level-offs, sharp turns, and implausible values.
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Normalize observations
Apply training weather and one start weight, reduced by estimated fuel burn.
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Fit the trend
Group climbs into 500-ft DA bins and fit typical and P90 trends.
The planner uses the typical trend. The -15% margin is a scenario, not a validated safety factor.
How this aircraft profile was created
A transparent record of the source data, assumptions, filtering, and limits behind the planner.
Scope
This is a descriptive model of one particular Cessna 120, identified here as the Personal Cessna 120 profile. It is based only on flights recorded in that aircraft. Differences in engine condition, propeller, rigging, weight, technique, instrumentation, and atmosphere mean these estimates should not be transferred to another aircraft—even another Cessna 120.
- Source flights
- 6
- Climb windows reviewed
- 1,667
- Model windows
- 550
- Model segments
- 8
- Observed DA range
- 2,032–12,294 ft
- 01
Record the flights
Six onboard GPS/KML tracks supplied timestamp, position, altitude, and groundspeed observations. Invalid altitude sentinels and malformed points were rejected before analysis.
- 02
Estimate density altitude
Historical temperature and sea-level pressure were sampled along each route. GPS altitude was converted to pressure altitude, temperature was adjusted for elevation, and density altitude was estimated for each climb window.
- 03
Find sustained climbs
Overlapping one-minute windows were grouped into sustained climbs. Gaps, level-offs, implausible values, insufficient altitude gain, and excessive course changes were excluded from the fitted model.
- 04
Normalize the weight
Each flight was assumed to begin at 1,250 lb and burn 4.5 gal/hr at 6.0 lb/gal. Observed climb was converted to a 1,450 lb gross-weight equivalent using the estimated weight at that point in the flight.
gross-equivalent climb = observed climb × estimated weight ÷ 1,450 - 05
Fit the empirical trend
Accepted climbs were grouped in 500-ft density-altitude bins. A weighted linear fit through the per-segment medians produced the typical planning trend.
typical climb at gross = 511.7 − 0.03329 × density altitude - 06
Build a departure scenario
The published-runway selector comes from a local build of the FAA 28-day NASR APT CSV, effective on the date shown in the runway selector. The build joins airport, runway, and runway-end records to obtain the identifier, true alignment, dimensions, surface, coordinates, and FAA runway-end elevation; when an end elevation is absent, the catalog falls back to airport reference elevation. For a selected takeoff runway, the comparison begins at the reciprocal end—the departure end of runway (DER)—and assumes crossing it 35 ft above DER elevation, matching the standard FAA departure-design basis. Ground roll, liftoff, and the ability to reach that height are not modeled. This inventory is not current runway status, so verify NOTAMs and authoritative flight information.
The planner adjusts the gross-weight trend to the takeoff weight entered for a scenario. It samples straight-course centerline terrain and a corridor that fans outward from the DER at 0.5 NM laterally per NM along track until it reaches the selected 0.5, 1, 2, or 5 NM half-width. Corridor-high terrain remains conservative and is shown separately from centerline terrain. A reviewed gradient trace stops at its published termination altitude because the app does not model procedure turns or assigned headings. Reviewed, cycle-dated departure gradients are procedure references only; the selected procedure and ATC clearance control. The separate −15% line is simply a conservative comparison scenario and has not been validated as a safety factor.
What this model does not establish
- It is not FAA-approved aircraft performance data and does not replace the aircraft flight manual, placards, operating limitations, or pilot judgment.
- It does not calculate weight and balance, center of gravity, takeoff distance, obstacle clearance, or engine/propeller condition.
- Its fit quality is in-sample. The source flights were not controlled flight tests, and the assumed start weights were not recorded for each flight.
- Terrain and weather services provide context only. Their availability, timing, resolution, and accuracy are not guaranteed.