Instrument Rating Checkride Practice Test

What advantage does using GPS as a primary means of navigation provide when using WAAS?

1. Increases fuel efficiency

2. Allows for lower decision altitudes

3. Reduces navigation complexity

4. Enhances aircraft speed

The correct answer is: Allows for lower decision altitudes

Using GPS as a primary means of navigation with Wide Area Augmentation System (WAAS) provides the significant advantage of allowing for lower decision altitudes. WAAS enhances the accuracy and integrity of GPS signals by correcting for atmospheric and other errors, which supports precision approaches and landings with significantly improved vertical guidance. As a result, pilots can operate under lower decision altitudes when executing approaches, which can enhance operational efficiency and safety. This capability is particularly beneficial in conditions where traditional navigational aids might require higher decision altitudes due to limitations in accuracy. Lower decision altitudes mean a more precise approach to landing, allowing for better utilization of airspace and access to airports that may be challenging to reach under traditional navigation methods. Other aspects like fuel efficiency, navigation complexity, and aircraft speed may be indirectly affected by the use of WAAS-enabled GPS navigation, but the most direct and operationally significant advantage relates to the capability of conducting approaches with lower decision altitudes.