Editing Standard rate turn (section)

=== Angle of bank formula ===

The formula for calculating the angle of bank for a specific [[true airspeed]] (TAS) in SI units (or other [[coherent system]]) is:<ref>[http://www.luizmonteiro.com/Article_Bank_Angle_for_Std_Rate_01.aspx LuizMonteiro.com Aviation Education]</ref>

<math>\phi = \arctan \frac{v_\mathrm{t}^2}{rg}</math>

where <math>\phi</math> is the angle of bank, <math>v_\mathrm{t}</math> is true airspeed, <math>r</math> is the radius of the turn, and <math>g</math> is the acceleration due to gravity.

For a rate-one turn and velocity in [[Knot (unit)|knots]] ([[nautical mile]]s per hour, symbol kn), this comes to

<math>\phi = \arctan \frac{\{v_\mathrm{t}\}_\mathrm{kn}} {364}</math>.

A convenient approximation for the bank angle in degrees is

<math>\phi / ^\circ \approx \frac{\{v_\mathrm{t}\}_\mathrm{kn}} {10} + 7</math>

For aircraft holding purposes, the [[International Civil Aviation Organization]] (ICAO) mandates that all turns should be made, "at a bank angle of 25° or at a rate of 3° per second, whichever requires the lesser bank."<ref>{{cite book
|title=Doc 8168 (PANS-OPS)
|edition=5
|year=2006
|publisher=ICAO
}}</ref> By the above formula, a rate-one turn at a TAS greater than 180 knots would require a bank angle of more than 25°. Therefore, faster aircraft just use 25° for their turns.