True Airspeed

{
  "asOf": "2026-10-11T14:44:09.099Z",
  "casKt": 150,
  "degraded": false,
  "densityRatio": 0.739,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "equivalentAirspeedKt": 149.57,
  "mach": 0.2727,
  "notChecked": [
    "indicated-to-calibrated correction: enter CAS, not raw IAS (the flight manual lists position error)",
    "ram-rise: at high speed the probe reads warmer than the static air, so enter the static temperature (total air temperature must be corrected)",
    "…2 more"
  ],
  "pressureAltitudeFt": 10000,
  "reasons": [
    "Calibrated airspeed is converted through the dynamic pressure it represents (isentropic flow, so compressibility is included), then TAS = Mach x speed of sound at the actual temperature.",
    "Actual temperature used for the speed of sound and density."
  ],
  "ruleOfThumbTasKt": 180,
  "source": "computed locally",
  "speedOfSoundKt": 638.1,
  "summary": "150 kt calibrated at 10000 ft and -5 C is 174 kt true airspeed (Mach 0.273); the 2%-per-1000-ft rule gives 180 kt.",
  "tasKt": 173.99,
  "tasMinusCasKt": 23.99,
  "temperatureC": -5,
  "verdict": "COMPUTED"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://aviation-calc.x402tookit.com/true-airspeed?casKt=150&oatC=-5&pressureAltitudeFt=10000'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://aviation-calc.x402tookit.com/true-airspeed?casKt=150&oatC=-5&pressureAltitudeFt=10000' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Faviation-calc.x402tookit.com%2Ftrue-airspeed
const res = await pay("https://aviation-calc.x402tookit.com/true-airspeed?casKt=150&oatC=-5&pressureAltitudeFt=10000");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://aviation-calc.x402tookit.com/true-airspeed?casKt=150&oatC=-5&pressureAltitudeFt=10000")
    print(res.status_code, res.text)