Which statement correctly describes required procedures?

• A. Flow control procedures only
• B. TMU reroutes only
• C. Neither must be followed
• D. Flow control procedures and TMU reroutes

Answer: (D)

The essential idea here is that both kinds of procedures are required together to manage traffic effectively. Flow control procedures regulate the overall entry and movement of traffic to prevent congestion and maintain safe separation, while TMU reroutes adjust flight paths to relieve specific bottlenecks and meet capacity demands. In practice, you follow flow control to control demand and timing, and you apply TMU reroutes to implement the necessary trajectory changes when needed. Relying on only one type misses important safety and efficiency steps: flow control alone can leave localized congestion unresolved, and rerouting alone can overlook broader, systemic flow limits. Therefore, the correct approach is to apply both flow control procedures and TMU reroutes as part of the required procedures.