Takeoff Performance

Calculate takeoff performance data including V-speeds, regulatory takeoff weight (RTOW), thrust settings, and distances.

Calculation Modes

The API supports two calculation modes depending on your use case. The mode is determined by the presence of the takeoffWeight parameter.

Request

Full Request Structure

{
  "query": "performance",
  "apiVersion": "1.3.6",
  "data": {
    "requestType": "TAKEOFF",
    "units": {
      "weight": "kg",
      "wind": "kt",
      "altitude": "feet",
      "distance": "feet",
      "depth": "mm",
      "pressure": "hpa"
    },
    "aircraft": {
      "file": "737-800W_CFM56-7B26.json",
      "userRegistration": null,
      "virtualAirline": null
    },
    "airport": "EBBR",
    "runway": "25R",
    "weather": {
      "windDirection": 250,
      "windSpeed": 10,
      "headwind": null,
      "temperature": 15,
      "qnh": 1013
    },
    "runwayCondition": {
      "state": "DRY",
      "depth": 0
    },
    "configuration": {
      "flap": "OPTIMUM",
      "rating": "OPTIMUM",
      "ratingAssumed": null,
      "antiIce": "OFF",
      "acBleed": "AUTO",
      "improvedClimb": "NO"
    },
    "weight": {
      "takeoffWeight": null,
      "flexibleTakeoffWeight": null,
      "cg": null,
      "cgPosition": null
    },
    "inopItems": {
      "mel": [1, 3],
      "cdl": []
    },
    "notam": {
      "shortenStart": 0,
      "shortenEnd": 200,
      "obstacleHeight": 0,
      "obstacleDistance": 0,
      "obstacleLateral": 0,
      "refHeight": "runwayStart",
      "refDistance": "runwayStart"
    },
    "imageFormat": "svg"
  }
}

Units

The API uses standard units by default. You can override any unit by specifying it in the units object. Response values will be returned in the same units.

Standard Units (Default)

Custom Units

Override defaults by including the units object:

"units": {
  "weight": "lb",
  "distance": "feet",
  "depth": "inches"
}

Parameters

aircraft Required

airport & runway Required

weather

runway_condition

configuration

weight

notam

NOTAM (Notice to Airmen) runway restrictions. When provided, the takeoff distances are adjusted to reflect temporary runway modifications. Requires NOTAM in subscription. Pass null or omit when not applicable.

The same shortenStart and shortenEnd values are used for both takeoff (adjusts TORA) and landing (adjusts LDA) calculations internally.

When the runway end is shortened (shortenEnd > 0), clearway and stopway are automatically set to zero. TORA, TODA and ASDA are derived from the shortened runway length.

All distance values use the distance unit and obstacle height uses the altitude unit from the units section (default: feet).

inopItems

imageFormat

Requested image format for graphic, cduGraphic and rtoGraphic. svg (the default) is always cheap to produce and is the canonical source the other formats are rendered from. Requesting png or jpg triggers a genuine Imagick rasterization pass, so pick it only when you actually need a raster image (e.g. for PDF export) — the response's svg field is populated either way.

Response

Response Structure

The response contains a performance object with three sub-objects: full (full thrust calculation), assumed (reduced thrust calculation when available), and additionalAssumed (an array of extra assumed-temperature calculations such as a user-requested custom FLEX temperature; empty unless requested).

{
  "performance": {
    "full": { ... },
    "assumed": { ... },
    "additionalAssumed": [ ... ]
  }
}

When assumed/flex thrust is not available, the assumed object contains only status fields:

"assumed": {
  "assumed": false,
  "assumedMessage": "No valid assumed temperature found for these conditions."
}

Additional Assumed Temperatures (optional, Airbus only)

additionalAssumed is an optional array of extra assumed-temperature calculations performed in parallel alongside the main TOGA / max-FLEX envelope. It is always present in the response but is empty ([]) by default and is only populated for Airbus aircraft when the client explicitly requests a custom FLEX temperature via configuration.ratingAssumed in the regulatory range 44–67 °C with a takeoff weight supplied. Boeing aircraft, windshear takeoffs, requests without a takeoff weight, and ratingAssumed values outside 44–67 °C all yield an empty array.

It currently holds at most one entry (the user's custom FLEX), but is structured as an array so future additional assumed scenarios can be appended without breaking clients.

Each entry always includes requested and available. When available is true, the entry also carries the same V-speeds, distances, N1, trim, margin, etc. fields documented under Performance Result Fields below (in the requested units and camelCase). When available is false, the entry includes an errorMessage explaining why the calculation could not be returned (e.g. the FLEX is too low for the requested weight, or the weight exceeds the performance-limited TOW at that thrust reduction).

"additionalAssumed": [
  {
    "requested": 55,
    "available": true,
    "assumed": true,
    "rating": "FLEX 55",
    "flap": "1+F",
    "temperature": 55,
    "v1": 142,
    "vr": 145,
    "v2": 150,
    "n1": "88.4",
    "accelerateStopDistanceOneEngine": 1820,
    "takeOffDistanceOneEngine": 1750,
    "margin": 950
  }
]

"additionalAssumed": [
  {
    "requested": 62,
    "available": false,
    "errorMessage": "ATOW (77111 KG / 169957 LB) EXCEEDS PERFORMANCE LIMITED TOW (73404 KG / 161826 LB)"
  }
]

All Intersections (ALL) VPT Global Pro

Selecting the intersection ALL (sent as the intersection token appended to the full-length runway, e.g. "runway": "25RALL") computes the full-length runway and every intersection of that runway in a single request.

• The full-length result is returned in the top-level performance object exactly as for a normal request (fully back-compatible).
• The full-length calculation runs first and acts as a gate: if it cannot be computed, the request returns that result only and the fan-out is skipped.
• This feature requires a VPT Global Pro subscription (is_allIntersections). Requests from accounts without this entitlement are rejected with "calculationPossible": false and an error stating the feature requires VPT Global Pro — no calculation is performed.
• When enabled, an additional intersections array is returned. Each entry identifies the runway and the intersection (taxiway label) for display, plus the units and a full performance object (full, assumed, additionalAssumed) identical in shape to the top-level result. Declared distances (TORA/TODA/ASDA) are inside each performance object as usual.

{
  "performance": { "full": { ... }, "assumed": { ... }, "additionalAssumed": [ ... ] },
  "intersections": [
    {
      "runway": "25R",
      "intersection": "B4",
      "units": { ... },
      "performance": {
        "full": { ... },
        "assumed": { ... },
        "additionalAssumed": [ ... ]
      }
    },
    {
      "runway": "25R",
      "intersection": "D",
      "units": { ... },
      "performance": { ... }
    }
  ]
}

An intersection entry where performance is not achievable (e.g. runway too short) carries "notAchievable": true and a caution message instead of units / performance. This is a normal, expected outcome for short intersections — the full-length result and any achievable intersections are unaffected. The full-length runway and every intersection are computed in parallel — all their provider calculations fire together in a single batched round-trip, so total time stays close to that of a single calculation regardless of how many intersections the runway has.

Status Fields

Configuration Fields

Weight Fields

V-Speed Fields

Engine Fields

Distance Fields

Climb Gradient Fields

Trim Fields

Engine Failure Procedure Fields

Brake Cooling Fields

"brakeCoolingSchedule": {
  "air": {
    "eighty": "0",
    "hundred": "5",
    "v1": "FUSE MELT"
  },
  "ground": {
    "eighty": "0",
    "hundred": "29",
    "v1": "FUSE MELT"
  }
}

Graphics Fields

"rtoDistance": {
  "eighty": 793,
  "hundred": 1239,
  "v1": 2678
}

Full Response Example

{
  "performance": {
    "full": {
      "assumed": false,
      "assumedMessage": "No valid assumed temperature found for these conditions.",
      "rating": "TO-1",
      "flap": "1",
      "lblTemp": "OAT",
      "lblThrust": "FULL TAKE OFF POWER",
      "temperature": 15,
      "tora": 11935,
      "isNotam": false,
      "displayVspeeds": true,
      "vrefIsDisplayed": false,
      "units": {
        "weight": "kgs",
        "distance": "ft",
        "height": "ft"
      },
      "tow": 73920,
      "structuralLimited": 79016,
      "tireSpeedLimit": 86183,
      "fieldLimited": 84060,
      "climbLimited": 76025,
      "obstacleClearanceLimited": 73920,
      "brakeEnergyLimited": 86183,
      "maxTow": 73920,
      "limitingFactor": "OBSTACLE CLEARANCE",
      "limitingFactorShort": "OBST.",
      "v1Logic": "Optimum",
      "v1": 156,
      "vr": 156,
      "v2": 159,
      "vman": 0,
      "vrMax": 0,
      "vrefFlaps": "40",
      "vrefSpeed": 150,
      "greenDot": 205,
      "n1Label": "N1",
      "n1": "91.7",
      "accelerateStopDistanceOneEngine": 8632,
      "takeOffRunAllEngines": 8152,
      "takeOffRunOneEngine": 7802,
      "takeOffDistanceAllEngines": 8821,
      "takeOffDistanceOneEngine": 8632,
      "margin": 3303,
      "secondSegmentGros": 2.71,
      "secondSegmentNet": 1.91,
      "trimRaw": "N/A",
      "trimRounded": "N/A",
      "efp": "Maintain 244° to 25 NM and HOLD.",
      "effra": 976,
      "effrh": 800,
      "userEffrValue": 976,
      "userEffrReference": "AMSL",
      "brakeCoolingSchedule": {
        "air": { "eighty": "0", "hundred": "5", "v1": "FUSE MELT" },
        "ground": { "eighty": "0", "hundred": "29", "v1": "FUSE MELT" }
      },
      "rtoDistance": { "eighty": 793, "hundred": 1239, "v1": 2678 },
      "graphic": {
        "svg": "http://example.com/takeoffResult.svg",
        "png": null,
        "jpg": null
      },
      "cduGraphic": {
        "svg": "http://example.com/takeoffResult_cdu_full.svg",
        "png": null
      },
      "rtoGraphic": {
        "svg": "http://example.com/rtoResult_full.svg",
        "png": null,
        "jpg": null
      },
      "flapAnnotation": "OPTIMUM"
    },
    "assumed": {
      "assumed": false,
      "assumedMessage": "No valid assumed temperature found for these conditions."
    },
    "additionalAssumed": []
  }
}