Certified Flight Instructor - Flight Instructor Airplane Practice Exam

Which is the most crucial action before descending for an approach?

1. Adjusting fuel mixture

2. Setting up navigation equipment

3. Checking the altimeter setting

The correct answer is: Checking the altimeter setting

Before commencing a descent for an approach, checking the altimeter setting is essential for ensuring that altitude readings are accurate. Accurate altitude information is critical in aviation, particularly when flying in controlled airspace or near other aircraft. By adjusting the altimeter to the local altimeter setting, pilots guarantee that their altitude is reported accurately relative to sea level. The altimeter setting affects the altitude that the aircraft maintains and contributes to safe separation from terrain and other aircraft. If the altimeter is not set correctly, it could lead to an incorrect perception of altitude, potentially causing the aircraft to be too high or too low during the approach, which could result in dangerous situations. While adjusting the fuel mixture and setting up navigation equipment are also important factors during flight preparation, the accuracy of altitude is fundamental to the safety of the approach and landing phases of flight. Thus, ensuring that the altimeter setting reflects the current conditions is the most critical action before beginning the descent.