Are "expected altitudes" on a STAR considered mandatory?

In the context of Standard Terminal Arrival Routes (STARs), "expected altitudes" are primarily designed for planning purposes. They serve as guidance for pilots to understand the vertical profile they should follow as they approach the airport. These altitudes help to organize air traffic and ensure a smooth, efficient flow into busy terminal areas. However, they are not enforced in the same manner as mandatory altitudes.

Pilots can often expect flexibility with these altitudes depending on air traffic control (ATC) instructions and current conditions, meaning that adherence is not obligatory. This allows for adjustments based on traffic, weather, and other operational considerations, making it crucial for pilots to maintain communication with ATC for any changes that might arise.

This understanding emphasizes that while expected altitudes contribute to a structured arrival into airports, they do not constitute mandatory requirements unless explicitly stated by ATC, which aligns with proper aircraft operation and safety protocols.