Which instrument provides information on the aircraft's angle of attack?

The instrument that provides information on the aircraft's angle of attack is the Angle of Attack (AoA) Indicator. This instrument is specifically designed to measure the angle between the oncoming air or relative wind and a reference line on the aircraft, typically the wing. The AoA is crucial for flight safety, as it helps pilots determine how close the aircraft is to reaching the critical angle of attack, beyond which a stall may occur.

In contrast, the other instruments listed have different functions. Fuel Flow measures the rate of fuel consumption, which is important for understanding fuel efficiency and operational range. The Vertical Speed Indicator (VSI) indicates whether the aircraft is climbing or descending and at what rate. The Altimeter measures the aircraft's altitude above sea level based on atmospheric pressure. While these instruments are vital for evaluating different aspects of flight, they do not provide specific information regarding the angle of attack. This makes the AoA Indicator the clear choice for understanding and managing aircraft performance relative to the airflow around the aircraft.