While operating in Class D airspace, each pilot of an aircraft approaching to land on a runway served by a visual approach slope indicator (VASI) shall

• A. Maintain an altitude at or above the glide slope until a lower altitude is necessary for a safe landing
• B. Descend below the glide slope as soon as possible
• C. Maintain altitude at or below the glide slope
• D. Adjust speed only

Answer: (A)

When using a VASI on approach in Class D airspace, you should fly at or above the glide slope until you can safely descend to land. The glide slope path is designed to provide a safe descent angle and obstacle clearance, so staying on or above it keeps you in a position where you can react to any surprises and still reach the runway. You should only lower below the glide slope when you have the runway environment in sight and a safe landing is achievable along the established path. Descent below the glide slope too early can put you on a steeper or lower path than designed, increasing the risk of undershooting or encountering obstacles. Simply adjusting speed does not substitute for proper altitude management on the glide path.