FAA Instrument Rating Written Practice Test

The Minimum Safe Altitude (MSA) is a critical element in instrument flight procedures, providing a safe altitude for aircraft while navigating in the vicinity of an airport. It ensures that the aircraft remains clear of obstacles and terrain surrounding the airport, particularly during approaches and missed approach procedures.

For the RNAV (GPS) X RWY 28L approach at Portland International Airport (PDX), an MSA of 5,800 feet Mean Sea Level (MSL) reflects the need for safe vertical clearance, especially in mountainous terrain or other potentially hazardous areas. This specific altitude allows for additional safety margins as pilots conduct their approaches, ensuring enough space above any obstructions.

The significance of selecting 5,800 feet MSL as the correct answer lies in the topographical considerations and air traffic regulations, which established this altitude based on the surrounding environment. It illustrates the importance of adhering to standardized altitudes in approach charts to mitigate risks associated with low-altitude flight, primarily in a dense airspace like that around major airports.

Understanding the MSA not only helps ensure safety during the approach phase but also reinforces the importance of comprehensive planning and awareness of one's environment when flying under instrument flight rules (IFR).