Rate 1 Turn Calculation

Standard Rate 1 Turn Calculator

function calculateRateOne() { var tas = parseFloat(document.getElementById("tasInput").value); if (isNaN(tas) || tas <= 0) { alert("Please enter a valid True Airspeed."); return; } // A Rate 1 turn is 3 degrees per second. // The formula for bank angle (theta) for a standard rate turn is: // tan(theta) = (Velocity * RateOfTurn) / gravity // Constant for Rate 1: omega = 3 deg/sec = 0.0523599 rad/sec // Gravity = 32.174 ft/s^2 // TAS to ft/s = knots * 1.68781 var velocityFps = tas * 1.68781; var omega = 0.0523599; // 3 degrees in radians var gravity = 32.174; var bankAngleRad = Math.atan((velocityFps * omega) / gravity); var bankAngleDeg = bankAngleRad * (180 / Math.PI); // Turn Radius = V / omega // Radius in feet = velocityFps / omega var radiusFt = velocityFps / omega; var radiusNm = radiusFt / 6076.12; // 1 NM = 6076.12 feet var diameterNm = radiusNm * 2; document.getElementById("bankAngleResult").innerHTML = bankAngleDeg.toFixed(1); document.getElementById("radiusResult").innerHTML = radiusNm.toFixed(2); document.getElementById("diameterResult").innerHTML = diameterNm.toFixed(2); document.getElementById("results").style.display = "block"; }

What is a Rate 1 Turn?

In aviation, a Rate 1 turn (also known as a Standard Rate Turn) is defined as a turn where the aircraft changes its heading at a rate of 3 degrees per second. This results in a complete 360-degree circle in exactly 2 minutes.

This is a fundamental concept for Instrument Flight Rules (IFR) pilots, as it allows for predictable maneuvering and navigation using timed turns if heading indicators fail.

The Bank Angle Formula

As True Airspeed (TAS) increases, the bank angle required to maintain a standard rate turn also increases. While the calculator uses the precise trigonometric formula, pilots often use a common Rule of Thumb:

Bank Angle ≈ (TAS / 10) + 7

For example, at 100 knots, the rule of thumb suggests 17° of bank. At 150 knots, it suggests 22°. Our calculator provides the mathematically precise requirement based on centrifugal force and aerodynamic load.

Why Turn Radius Matters

The radius of the turn is critical for remaining within protected airspace during holding patterns or procedure turns. As shown by the calculator, as your TAS increases, your turn radius expands significantly. This means faster aircraft require much larger areas to complete a 180-degree or 360-degree course change.

Practical Aviation Examples

True Airspeed (TAS)	Approx. Bank Angle	Turn Radius
90 Knots	13.8°	0.48 NM
120 Knots	18.2°	0.64 NM
200 Knots	28.7°	1.06 NM

Key Takeaways for Pilots

• Time is Constant: Regardless of speed, a Rate 1 turn always takes 60 seconds for 180° and 120 seconds for 360°.
• Bank Limits: In most civil aviation, standard rate turns are capped at 25° or 30° for passenger comfort and safety, even if the TAS requires more.
• Speed Dependency: Faster aircraft have much larger turn radii. This is why high-speed jets often perform "Half-Standard Rate" turns at high altitudes to avoid excessive bank angles.