What do "crossing restrictions" on an approach chart indicate?

Crossing restrictions on an approach chart indicate the required altitude at which an aircraft must cross a specific waypoint. These restrictions are crucial for ensuring safe vertical separation between aircraft during the approach phase of flight. They help in maintaining a standard procedure for pilots to follow, preventing conflicts and enhancing safety as aircraft maneuver through varying altitudes and airspace.

When an approach chart specifies a crossing restriction, it often reflects either regulatory requirements or optimized flight paths that contribute to efficient air traffic flow. Pilots must adhere to these altitudes to maintain safe distances from terrain, obstacles, and other aircraft, thereby ensuring effective navigation during the critical phases of approach and landing.