What altimeter setting is required crossing into FL180?

What altimeter setting is required crossing into FL180?

• A. 30.12
• B. 28.92
• C. 29.92
• D. 29.50

Answer: (C)

Crossing into flight levels uses a standard pressure reference so every aircraft reads the same altitude regardless of local weather. Above the transition altitude, you set the altimeter to 29.92 inches of mercury (1013 hPa). This standard pressure makes the instrument show flight levels instead of true altitude based on local sea-level pressure, ensuring consistent vertical separation in shared airspace. The other values are not the standard reference and would give you readings that don’t align with the actual pressure level.

Crossing into flight levels uses a standard pressure reference so every aircraft reads the same altitude regardless of local weather. Above the transition altitude, you set the altimeter to 29.92 inches of mercury (1013 hPa). This standard pressure makes the instrument show flight levels instead of true altitude based on local sea-level pressure, ensuring consistent vertical separation in shared airspace. The other values are not the standard reference and would give you readings that don’t align with the actual pressure level.