What is the primary instrument used for bank during a steep turn?

The primary instrument used for maintaining bank during a steep turn is the attitude indicator. This instrument displays the orientation of the aircraft relative to the horizon, showing whether the wings are level or if the aircraft is banking. When performing a steep turn, the pilot relies on the attitude indicator to set and maintain the appropriate angle of bank, ensuring that the turn is executed safely and effectively.

The attitude indicator is essential for avoiding excessive bank angles, which could lead to loss of control or even a stall if not monitored correctly. By observing the attitude indicator, the pilot can make the necessary adjustments during the turn to maintain altitude and ensure a smooth, coordinated turn.

While the altimeter, airspeed indicator, and vertical speed indicator provide important information regarding altitude, speed, and the rate of climb or descent, they do not specifically assist in maintaining or monitoring the aircraft's bank angle, which is crucial during steep turns.