What describes flight levels in aviation terms?

What describes flight levels in aviation terms?

• A. Used for altitudes above 18,000 feet; numbers are the altitude with the last 2 digits removed.
• B. Used for altitudes below 10,000 feet; numbers indicate altitude in feet.
• C. Used for all airspace; numbers show altitude in tens of feet.
• D. Used for oceanic routes only; numbers represent thousands of feet.

Answer: (A)

Flight levels are a way of expressing altitude using a standard pressure setting to ensure consistent vertical separation. They’re used above the transition altitude (18,000 feet in the US and many other regions). At that level, the altimeter is set to 1013 hPa, and the flight level shown is the pressure altitude divided by 100. So FL180 corresponds to 18,000 feet pressure altitude. That’s why the description describing flight levels as used above 18,000 feet with the number representing the altitude with the last two digits removed is the best fit. Below the transition altitude, altitudes are given in feet with local pressure settings, not as flight levels. Flight levels aren’t limited to oceanic routes or to any single airspace; they apply to high-altitude en route flight where standard pressure is used.

Flight levels are a way of expressing altitude using a standard pressure setting to ensure consistent vertical separation. They’re used above the transition altitude (18,000 feet in the US and many other regions). At that level, the altimeter is set to 1013 hPa, and the flight level shown is the pressure altitude divided by 100. So FL180 corresponds to 18,000 feet pressure altitude. That’s why the description describing flight levels as used above 18,000 feet with the number representing the altitude with the last two digits removed is the best fit. Below the transition altitude, altitudes are given in feet with local pressure settings, not as flight levels. Flight levels aren’t limited to oceanic routes or to any single airspace; they apply to high-altitude en route flight where standard pressure is used.