Which button is used to engage the CLB or DES mode?

• A. Engage the GA mode
• B. Engage the CLB or DES mode
• C. Engage the NAV mode
• D. Engage the HOLD mode

Answer: (B)

Engaging CLB or DES is about letting the autopilot manage vertical motion to climb or descend along the approved flight path. The button labeled CLB/DES specifically activates the vertical mode that handles climbs and descents, switching to climb when a ascent is wanted and to descent when a lower altitude is requested, following the configured guidance. This is different from the other buttons: going around (GA) starts a miss by climbing away, navigation (NAV) locks onto the flight plan track, and hold (HOLD) keeps the aircraft in a fixed state such as altitude or heading. So the button you press to engage CLB or DES is the CLB/DES control.