Before using SPEED, V/S or Pitch mode to change altitude, what must first be done?

• A. Select a new altitude with the ALT knob
• B. Engage the autopilot
• C. Disable the flight director
• D. Trim the aircraft to the new altitude

Answer: (A)

Setting a target altitude with the ALT knob is the essential first step before using SPEED, V/S, or PITCH to change altitude. The vertical modes need a destination to reach, and the ALT knob provides that goal for the autopilot/flight guidance system. Once the target altitude is set, you can engage a vertical mode to begin climbing or descending toward it. Engaging the autopilot or the flight director isn’t required by itself, and disabling the flight director isn’t necessary for altitude changes. Trimming adjusts airframe balance, not the commanded altitude, so it won’t move the aircraft to a new altitude on its own.