Equal time point API

Computes the equal-time (critical) point between two airfields from total distance and the out/back ground speeds. Answers 'Where is the ETP where continuing and turning back take equal time?', 'What is my critical point with these winds?'.

Price$0.04per request

MethodPOST

Route/v1/nav/equal-time-point

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

aviationetpequal-time-pointcritical-pointdiversionflight-planningetopsground-speed

API URLhttps://x402.hexl.dev/v1/nav/equal-time-point

Integration docs

Example request

{
  "totalDistanceNm": 1000,
  "groundSpeedOnKt": 400,
  "groundSpeedBackKt": 500
}

Example response

{
  "distanceToEtpNm": 555.6,
  "timeToEtpHr": 1.389,
  "timeToEtpMin": 83.3,
  "interpretation": "Equal-time point 555.6 nm from departure (83.3 min): from here it takes the same time to continue or turn back."
}

Input schema

{
  "type": "object",
  "required": [
    "totalDistanceNm",
    "groundSpeedOnKt",
    "groundSpeedBackKt"
  ],
  "properties": {
    "totalDistanceNm": {
      "type": "number",
      "examples": [
        1000
      ]
    },
    "groundSpeedOnKt": {
      "type": "number",
      "examples": [
        400
      ]
    },
    "groundSpeedBackKt": {
      "type": "number",
      "examples": [
        500
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}