Definition
A bank angle of 45 degrees from wings-level, used in instrument flying as the defining bank angle for a steep turn. At this angle the aircraft's lift vector is tilted well off vertical, requiring increased back pressure and, in most cases, added power to maintain altitude and airspeed.
Plain English
The wings are tilted 45 degrees from level — halfway between flat and straight up on edge. In instrument training, this is the standard bank used to practice steep turns.
Context Anchor
Seen in steep-turn training and instrument flying when the pilot is asked to establish and hold a specific bank angle.
Derivation
Bank comes from older words for a raised edge or slope. That helps because an airplane in a bank is no longer level; it is sloped to one side.
Why Pilots Care
A 45-degree bank increases load factor and requires precise coordination to maintain altitude and prevent slipping or skidding.
Intuition Check
Bank here does not mean money or the side of a river. In flying, bank means how far the airplane’s wings are tilted left or right; 45° is a fairly steep tilt.
Example Sentence 1
The examiner asked for a 45° bank steep turn to the left, holding altitude within 100 feet.
Example Sentence 2
At a 45° bank the pilot applied coordinated rudder pressure to keep the turn smooth and prevent any slip.