What must be recorded on the flight progress strip regarding altitude?

Recording the assigned altitude and any additional entry altitude on the flight progress strip is crucial for several reasons relating to air traffic control operations. The assigned altitude indicates the specific altitude at which an aircraft is operating or will operate, enabling controllers to ensure proper vertical separation between aircraft. This is vital for maintaining safety and preventing conflicts in airspace, especially in more congested areas.

The additional entry altitude, which is typically the altitude at which the aircraft will enter a new phase of flight (such as climbing or descending), provides controllers with valuable information about the aircraft's intended trajectory. This helps in coordinating handoffs between different controllers and maintaining awareness of an aircraft's flight profile. Furthermore, having both the assigned altitude and the additional entry altitude recorded allows for accurate tracking of an aircraft's altitude during its journey, ensuring that all parties involved in air traffic management are up to date with the current status of the flight.

While knowing the current altitude and ground level are important, they do not provide the comprehensive information necessary for effective air traffic management as the assigned and additional entry altitudes do. This comprehensive recording allows controllers to manage the flow of air traffic in a controlled manner, promoting efficiency and safety within the airspace.