What must the pilot in command make sure of when submitting changes to the flight plan?

The pilot in command is responsible for ensuring that any changes to the flight plan are submitted correctly, and the correct approach is to send only the changes to the facility that processed the original documentation. This is because the original flight plan is typically stored by the air traffic control facility, and they need to be updated on any adjustments to the planned route, altitude, or other relevant information.

By submitting changes directly to the facility that managed the initial filing, the pilot ensures that all modifications are logged in the official records, maintaining accurate and up-to-date information for air traffic control and ensuring they can provide proper guidance and assistance during the flight. This process also helps streamline communication and reduces the chance of confusion by keeping the information centralized.

In contrast, informing all flight crew immediately while potentially useful for internal communication does not address the regulatory obligation for notifying the controlling facility about the changes. Keeping the flight plan confidential does not align with the need for transparency and coordination with air traffic control, which is essential for safety and operational efficiency. Filing a new plan every time changes occur might unnecessarily complicate the process and create unnecessary workload, as updates to the existing plan are often sufficient and required.