Airport Runway Performance Demo

This dashboard is a curated advisory demo for runway operations. It blends short-range HRRR and RAP forecasts with a small runway catalog and reference aircraft profiles to estimate headwind / crosswind components, pressure and density altitude, and a rough runway margin over time.

Under the hood, the page resolves runway geometry and aircraft coefficients from lightweight metadata endpoints, then issues a standard GribStream /api/v2/[dataset]/timeseries request with forecast variables plus chained calculated expressions. That means the aviation-specific logic is transparent and reproducible from the public API rather than hidden behind a custom server-side endpoint.

What the controls do

• Airport / runway: selects the field elevation, runway heading, runway length, and forecast point.
• Aircraft: switches between curated reference profiles with different baseline distances and stall speeds.
• Weight slider: scales the reference distances to show how runway demand changes as payload changes.
• Surface state: applies a conservative multiplier for wet or contaminated runway conditions.

How to read the panels

• Runway requirement timeline: compares estimated takeoff and landing requirement against available runway length.
• Wind alignment theatre: shows headwind, tailwind, crosswind, and gust-driven crosswind relative to the selected runway heading.
• Altitude stack: tracks pressure altitude and density altitude, which often dominate high-field performance.
• Advisory strip: condenses each valid hour into the metrics that typically matter first in a briefing.

The formulas are intentionally simple and conservative: they use forecast weather plus aircraft-specific reference numbers and generic penalties / credits for density altitude, tailwind, headwind, weight, and runway condition. This is useful for demos, planning conversations, and customer presentations.

Representative GribStream request

The example below is the same style of request the dashboard makes for KASE RWY 15 with a Cessna 172S reference profile. The field elevation, runway heading, runway length, and aircraft coefficients come from the metadata endpoints, while the weather variables and derived performance fields are computed in one standard API call.

curl -X POST 'https://gribstream.com/api/v2/hrrr/timeseries' \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Bearer [API_TOKEN]' \
  -d '{
    "fromTime": "2026-04-11T17:42:52Z",
    "untilTime": "2026-04-12T12:42:52Z",
    "minLeadTime": "0h",
    "maxLeadTime": "36h",
    "coordinates": [
      { "lat": 39.2232, "lon": -106.8688, "name": "KASE RWY 15" }
    ],
    "variables": [
      { "name": "TMP", "level": "2 m above ground", "alias": "temp_k" },
      { "name": "DPT", "level": "2 m above ground", "alias": "dew_k" },
      { "name": "PRES", "level": "surface", "alias": "pres_pa" },
      { "name": "GUST", "level": "surface", "alias": "gust_ms" },
      { "name": "UGRD", "level": "10 m above ground", "alias": "u_ms" },
      { "name": "VGRD", "level": "10 m above ground", "alias": "v_ms" }
    ],
    "expressions": [
      { "expression": "temp_k - 273.15", "alias": "temp_c" },
      { "expression": "dew_k - 273.15", "alias": "dew_c" },
      { "expression": "pres_pa / 3386.389", "alias": "station_inhg" },
      { "expression": "station_inhg / func.Pow(1 - (7820 * 0.3048) / 44330.0, 5.255)", "alias": "altimeter_inhg" },
      { "expression": "func.Hypot(u_ms, v_ms) * 1.94384", "alias": "wind_kt" },
      { "expression": "gust_ms * 1.94384", "alias": "gust_kt" },
      { "expression": "(int(270 - func.Atan2(v_ms, u_ms) * 180 / 3.14159) + 360) % 360", "alias": "wind_dir_deg" },
      { "expression": "(wind_dir_deg - 150) * 3.14159 / 180", "alias": "angle_rad" },
      { "expression": "wind_kt * func.Cos(angle_rad)", "alias": "headwind_kt" },
      { "expression": "func.Max(headwind_kt, 0.0)", "alias": "headwind_pos_kt" },
      { "expression": "func.Max(-headwind_kt, 0.0)", "alias": "tailwind_kt" },
      { "expression": "func.Abs(wind_kt * func.Sin(angle_rad))", "alias": "crosswind_kt" },
      { "expression": "func.Abs(gust_kt * func.Sin(angle_rad))", "alias": "gust_crosswind_kt" },
      { "expression": "7820 + (29.92 - altimeter_inhg) * 1000", "alias": "pressure_alt_ft" },
      { "expression": "15 - 1.98 * pressure_alt_ft / 1000", "alias": "isa_temp_c" },
      { "expression": "pressure_alt_ft + 120 * (temp_c - isa_temp_c)", "alias": "density_alt_ft" },
      { "expression": "9.600", "alias": "crosswind_baseline_kt" },
      { "expression": "1630 * func.Pow(90 / 100.0, 1.7) * (1 + func.Max(density_alt_ft, 0.0) / 1000.0 * 0.140) * 1.0 * (1 + tailwind_kt * 0.040) / func.Max(0.75, 1 + headwind_pos_kt * 0.012)", "alias": "takeoff_req_ft" },
      { "expression": "1335 * func.Pow(90 / 100.0, 1.45) * (1 + func.Max(density_alt_ft, 0.0) / 1000.0 * 0.050) * 1.0 * (1 + tailwind_kt * 0.030) / func.Max(0.80, 1 + headwind_pos_kt * 0.010)", "alias": "landing_req_ft" },
      { "expression": "8006", "alias": "runway_length_ft" },
      { "expression": "runway_length_ft - takeoff_req_ft", "alias": "takeoff_margin_ft" },
      { "expression": "runway_length_ft - landing_req_ft", "alias": "landing_margin_ft" },
      { "expression": "func.Min(takeoff_margin_ft, landing_margin_ft)", "alias": "min_margin_ft" }
    ]
  }'

Why the math is defensible

• Wind components: headwind and crosswind are standard vector decomposition terms using wind * cos(angle) and wind * sin(angle).
• Pressure altitude: the demo uses the common pilot rule-of-thumb form field elevation + (29.92 - altimeter setting) * 1000.
• Density altitude: it then applies the standard approximation pressure altitude + 120 * (OAT - ISA temperature).
• Runway requirement: the resulting weather penalties are layered on top of reference takeoff / landing distances so users can see how sensitive performance is to wind, density altitude, weight, and runway condition.

Background and references: GribStream expressions · FAA Pilot's Handbook of Aeronautical Knowledge · FAA Airplane Flying Handbook · Pressure altitude · Density altitude.

Not for operational use. This page is not a substitute for the aircraft flight manual, airport data package, company SOPs, or dispatch / pilot performance calculations. Use it as a visual explainer for what GribStream can power, not as a go / no-go authority.