The maximum altitude limit of 400 feet is measured as feet above ground level.

The maximum altitude limit of 400 feet is measured as feet above ground level.

• A. Above Ground Level
• B. Above Mean Sea Level
• C. Above Ground Elevation
• D. Above Terrain

Answer: (A)

The limit is defined as feet above ground level, meaning the height is measured from the ground directly beneath the aircraft. This keeps the limit consistent with the local terrain and obstacles; you can be 400 ft above the surface of a hill even though your height above sea level is higher. It prevents the limit from changing with terrain elevation, which wouldn’t reflect how close you are to nearby obstacles. So, over flat ground you’d be at 400 ft MSL as well as 400 ft AGL, but over a hill you’d be higher above sea level while still only 400 ft above the ground. That’s why the correct interpretation is feet above ground level.

The limit is defined as feet above ground level, meaning the height is measured from the ground directly beneath the aircraft. This keeps the limit consistent with the local terrain and obstacles; you can be 400 ft above the surface of a hill even though your height above sea level is higher. It prevents the limit from changing with terrain elevation, which wouldn’t reflect how close you are to nearby obstacles. So, over flat ground you’d be at 400 ft MSL as well as 400 ft AGL, but over a hill you’d be higher above sea level while still only 400 ft above the ground. That’s why the correct interpretation is feet above ground level.