Mach & speed of sound API

Computes Mach number, local speed of sound and flight regime from TAS and either OAT or pressure altitude (ISA). Answers 'What is my Mach at FL350?', 'What is the speed of sound at this temperature?'.

Price$0.04per request

MethodPOST

Route/v1/nav/mach-speed-of-sound

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

aviationmachspeed-of-soundtransonicisaaltitudeairspeedsonic

API URLhttps://x402.hexl.dev/v1/nav/mach-speed-of-sound

Integration docs

Example request

{
  "trueAirspeedKt": 480,
  "pressureAltitudeFt": 35000
}

Example response

{
  "machNumber": 0.833,
  "speedOfSoundKt": 576.4,
  "speedOfSoundMs": 296.5,
  "oatC": -54.3,
  "flightRegime": "transonic",
  "interpretation": "Mach 0.833 (transonic); local speed of sound 576 kt at -54.3 deg C."
}

Input schema

{
  "type": "object",
  "required": [
    "trueAirspeedKt"
  ],
  "properties": {
    "trueAirspeedKt": {
      "type": "number",
      "examples": [
        480
      ]
    },
    "oatC": {
      "type": "number",
      "examples": [
        -54.3
      ]
    },
    "pressureAltitudeFt": {
      "type": "number",
      "examples": [
        35000
      ]
    }
  }
}

Output schema

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