What minimum altitude is necessary to vertically clear the obstacle on the northeast side of Airpark East Airport by 500 ft?

To determine the minimum altitude required to clear an obstacle by 500 feet, you first need to know the elevation of the obstacle itself. The essential calculation involves taking the height of the obstacle above mean sea level (MSL) and adding the clearance requirement of 500 feet.

If the obstacle on the northeast side of Airpark East Airport has an elevation of 773 feet MSL, for instance, you would add the 500-foot clearance to this elevation:

773 ft + 500 ft = 1273 ft MSL.

This results in an altitude of 1273 feet MSL needed to safely clear the obstacle by the required margin. Therefore, the answer that aligns with this calculation is 1273 ft MSL, which is why it is the correct choice.