Definition
A condition in multiengine flight, following the failure of one engine, in which the airplane is banked beyond the small angle (typically about 5 degrees toward the operating engine) needed to maintain coordinated, controlled flight. Excessive bank in this situation reduces climb performance, increases induced drag, lowers the stall margin, and can compromise directional control near minimum control airspeed (VMC).
Plain English
When one engine quits on a twin, the pilot needs to tilt the wings just slightly toward the still-running engine to keep the airplane straight and climbing. If the pilot tilts too far, the airplane stops climbing well, gets harder to control, and is closer to stalling.
Context Anchor
Encountered in multi-engine airplane training when discussing one-engine-inoperative climb performance after an engine failure.
Derivation
“Bank” in aviation means tilting the airplane left or right around its lengthwise axis. This is different from a money bank. “Engine-out” means an engine is not producing useful power, so the phrase points to a tilted airplane being flown with one engine failed.
Why Pilots Care
Excessive bank reduces the aircraft's ability to climb and can cause loss of control if Vmc is exceeded, directly affecting safety during critical phases like takeoff.
Grounding Statement
With one engine failed, the airplane has little extra power available, so every unnecessary degree of bank makes climbing harder.
Intuition Check
Do not assume “bank” means any normal turn is acceptable here. In engine-out flight, a small bank may help, but excessive bank means too much tilt for the airplane’s limited remaining performance.
Example Sentence 1
During the engine-out demonstration, the instructor pointed out that an excessive bank engine-out flight attitude was costing them nearly 200 feet per minute of climb.
Example Sentence 2
Applying excessive bank in engine-out flight increased the airspeed required for directional control.