How is "flight level" conventionally expressed in aviation?

• A. In feet above sea level
• B. In meters above ground level
• C. In hundreds of feet
• D. In nautical miles

Answer: (C)

In aviation, "flight level" refers to a specific altitude expressed in hundreds of feet. This convention is used primarily when an aircraft is flying at altitudes above the transition altitude, which is where the altimeter is set to the standard pressure setting of 29.92 inches of mercury, or 1013.25 hPa.

When saying a plane is flying at a flight level of 350, it denotes that the aircraft is at an altitude of 35,000 feet above sea level, under the assumption that the standard atmospheric conditions are present. This method of reporting altitude helps to ensure clarity and consistency among pilots and air traffic controllers during flight, especially in airspace where multiple aircraft are operating.

Although other expressions of altitude exist in aviation, such as feet above sea level, meters above ground level, and distances in nautical miles, these do not apply to the convention of flight levels. Flight levels are not expressed in meters or nautical miles, and foot measurements would need to be converted into hundreds of feet to align with what is recognized as flight level. Thus, the correct response highlights an established standard that enhances the safety and efficiency of air traffic management.