Table of Contents
Bank Angle in Coordinated Turns
When an aircraft or vehicle makes a level turn, it must bank (tilt) so that a component of the lift force provides the centripetal force needed for circular motion. The required bank angle depends on the speed and the radius of the turn. Faster speeds or tighter turns require steeper bank angles.
In aviation, understanding bank angle is critical for flight safety. Standard rate turns (3 degrees per second) are used in instrument flying. The bank angle determines the g-loading on the aircraft and its occupants, stall speed increase, and the turn radius for airspace planning.
Bank Angle Formula
Where theta is the bank angle, v is the speed, g is gravitational acceleration, and r is the turn radius. The load factor tells you how many g-forces the aircraft and pilot experience in the banked turn.
Bank Angle vs. G-Loading
| Bank Angle | G-Loading | Stall Speed Increase |
|---|---|---|
| 15° | 1.04 g | 2% |
| 30° | 1.15 g | 7% |
| 45° | 1.41 g | 19% |
| 60° | 2.00 g | 41% |
| 75° | 3.86 g | 97% |
FAQ
What is a standard rate turn?
A standard rate turn completes 360 degrees in 2 minutes, or 3 degrees per second. This is the standard used in instrument flying. The bank angle needed for a standard rate turn increases with airspeed: about 15 degrees at 100 knots and 25 degrees at 200 knots.
Why does stall speed increase in a bank?
In a banked turn, the lift must support both the aircraft weight and provide centripetal force. The total required lift increases by the load factor. Since stall speed increases with the square root of the load factor, a 60-degree bank (2g) increases stall speed by 41%.
What is the maximum bank angle for airliners?
Most airlines limit bank angles to 25-30 degrees for passenger comfort. The aircraft structural limit is typically 67 degrees (2.5g) for transport category aircraft. In emergency situations, pilots are trained to use up to 60 degrees of bank for collision avoidance maneuvers.