Turn Hold

{
  "asOf": "2026-10-11T14:44:09.365Z",
  "bankDeg": 18.24,
  "bankRuleOfThumbDeg": 19,
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "holdLegLengthNm": 2,
  "holdLegMinutes": 1,
  "holdPatternFuelNote": "multiply the pattern time by your hourly fuel flow",
  "holdPatternMinutes": 4,
  "holdWidthNm": 1.273,
  "loadFactorG": 1.053,
  "notChecked": [
    "wind: a hold flown in wind drifts, and entry procedures, wind correction and outbound timing adjustments are not modelled",
    "holding speed limits and the published pattern (inbound course, left or right turns, leg length in nm): follow the chart and ATC",
    "…2 more"
  ],
  "reasons": [
    "Turn rate = g tan(bank) / TAS (about 1092 x tan(bank) / TAS in knots, degrees per second); radius = TAS^2 / (g tan(bank)).",
    "The 'TAS / 10 + 7' rule of thumb gives a standard-rate bank of 19 degrees.",
    "…1 more"
  ],
  "secondsFor360": 120,
  "source": "computed locally",
  "stallSpeedIncreasePercent": 2.6,
  "summary": "At 120 kt, a bank of 18.2 degrees gives 3 degrees per second (a 360 takes 120 s), turn radius 0.637 nm (3868 ft), load factor 1.05 g. A holding pattern with 1-minute legs is 2 nm long and 1.27 nm wide…",
  "tasKt": 120,
  "turnDiameterNm": 1.2732,
  "turnRadiusFt": 3868,
  "turnRadiusNm": 0.6366,
  "turnRateDegPerSec": 3,
  "verdict": "STANDARD_RATE_TURN"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://aviation-calc.x402tookit.com/turn-hold?altitudeFt=5000&rateDegPerSec=3&tasKt=120'

# 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/turn-hold?altitudeFt=5000&rateDegPerSec=3&tasKt=120' \
  | 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%2Fturn-hold
const res = await pay("https://aviation-calc.x402tookit.com/turn-hold?altitudeFt=5000&rateDegPerSec=3&tasKt=120");
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/turn-hold?altitudeFt=5000&rateDegPerSec=3&tasKt=120")
    print(res.status_code, res.text)