What is the difference between BAC and BRC and when should each be used?

• A. BAC optimizes obstacle clearance distance; BRC optimizes time to climb; select based on terrain and performance needs.
• B. BAC is for best turn rate; BRC for best cruise speed.
• C. BAC and BRC are identical.
• D. BAC determines landing distance; BRC determines fuel economy.

Answer: (B)

This is about two climb-performance options used in planning departures. Best Angle of Climb (BAC) is the climb path that gives the greatest altitude gain per unit of horizontal distance. You’d choose BAC when you need to clear obstacles or reach a certain altitude with the least ground distance, so the climb is steeper and covers less horizontal area.

Best Rate of Climb (BRC) is the climb path that provides the greatest increase in altitude per unit time, i.e., the highest vertical speed. This is the choice when reaching a safe altitude quickly is the priority, such as to clear terrain or weather, even though the climb angle may be shallower than BAC.

The other ideas—like turn rate or cruise speed—don’t describe these climb performance concepts. BAC focuses on climbing steeply to minimize distance to a target altitude, while BRC focuses on climbing fast to reach altitude quickly.