Bank angle is the angle between an aircraft's wings and the horizontal horizon during a turn. The greater the bank angle, the more the aircraft tilts sideways, and the tighter the resulting turn.
How It Works#
When a pilot rolls the aircraft left or right, the wings tilt away from level flight. The angle of that tilt, measured from the horizon to the lateral axis of the wings, is the bank angle. A bank angle of 0° means wings-level. A bank angle of 90° means the wings point straight up and down.
As bank angle increases, lift splits into two components. One component continues to act vertically, supporting the aircraft's weight. The other acts horizontally, pulling the aircraft into the turn. To maintain altitude, the pilot must increase back pressure on the controls to raise the nose and compensate for the reduced vertical lift.
This also increases load factor, the ratio of lift to the aircraft's weight. At 60° of bank, the load factor reaches 2g, meaning the aircraft and everything in it experiences twice its normal weight. Stall speed also rises with load factor, which is why steep turns require careful airspeed management.
Bank angles are generally grouped by steepness:
- Shallow bank: less than 20°
- Medium bank: 20° to 45°
- Steep bank: above 45°
Example in Aviation#
A student pilot practices a standard-rate turn during flight training. A standard-rate turn rotates the aircraft at exactly 3° per second, completing a full 360° circle in two minutes. At typical training speeds, this requires roughly 15° to 25° of bank. The instructor reminds the student to add slight back pressure to hold altitude as the bank increases. Without that input, the nose drops and altitude is lost.
Why It Matters#
Bank angle directly controls turn rate and turn radius. A shallower bank produces a wider, gentler turn. A steeper bank tightens the turn but demands more from both the aircraft and the pilot. Understanding this relationship is essential for safe maneuvering, especially in congested airspace or during instrument approaches.
Exceeding the structural limit of the aircraft, or entering a steep bank without managing airspeed, can lead to a graveyard spiral. This is a dangerous descending turn where the aircraft accelerates rapidly. Pilots who understand bank angle and load factor are far better equipped to recognize and recover from unusual attitudes.
Key Takeaways#
- Bank angle is the tilt of the wings measured from the horizontal horizon.
- Greater bank angle means a tighter turn and higher load factor.
- Load factor doubles at 60° of bank, reaching 2g.
- Pilots must add back pressure in a bank to maintain altitude.
- Steep banks raise stall speed and demand precise airspeed control.