What altitude correction would be required on an RNAV approach into Glacier Park International airport at M20/M25 in the given METAR?

What altitude correction would be required on an RNAV approach into Glacier Park International airport at M20/M25 in the given METAR?

• A. 500 feet
• B. 350 feet
• C. 450 feet
• D. 600 feet

Answer: (B)

For RNAV approaches, altitude corrections are important to ensure the aircraft is operating safely and efficiently during its approach phase. The correct answer, which indicates a requirement for a 350-foot altitude correction, typically stems from analyzing both the airport elevation and the reported altimeter setting at the time of the approach. The altitude correction accounts for the difference between the standard atmospheric pressure at sea level (29.92 inHg) and the current altimeter setting provided in the METAR, as well as the elevation of the airport itself. In the case of Glacier Park International Airport, if the reported altimeter setting is higher than 29.92 inHg, a decrease in altitude is necessary, which could lead to the need for a specific correction based on the difference calculated. The reason for selecting a 350-foot adjustment is that it represents the appropriate change based on both the airport’s elevation relative to the associated altimeter setting and the specific requirements of the RNAV approach procedure. It displays an understanding of how both environmental factors and aviation regulations dictate adjustments in altitude for safe navigation, particularly in varying atmospheric conditions present during winter operations. Thus, this correction helps maintain the minimum safe altitude during the approach as required by the RNAV procedures.

For RNAV approaches, altitude corrections are important to ensure the aircraft is operating safely and efficiently during its approach phase. The correct answer, which indicates a requirement for a 350-foot altitude correction, typically stems from analyzing both the airport elevation and the reported altimeter setting at the time of the approach.

The altitude correction accounts for the difference between the standard atmospheric pressure at sea level (29.92 inHg) and the current altimeter setting provided in the METAR, as well as the elevation of the airport itself. In the case of Glacier Park International Airport, if the reported altimeter setting is higher than 29.92 inHg, a decrease in altitude is necessary, which could lead to the need for a specific correction based on the difference calculated.

The reason for selecting a 350-foot adjustment is that it represents the appropriate change based on both the airport’s elevation relative to the associated altimeter setting and the specific requirements of the RNAV approach procedure. It displays an understanding of how both environmental factors and aviation regulations dictate adjustments in altitude for safe navigation, particularly in varying atmospheric conditions present during winter operations. Thus, this correction helps maintain the minimum safe altitude during the approach as required by the RNAV procedures.