What is the purpose of a flight plan?

The primary purpose of a flight plan is to inform air traffic control (ATC) of the intended route a flight will take. This includes vital information such as the departure and destination airports, anticipated flight altitudes, waypoints along the route, and estimated departure and arrival times. By filing a flight plan, pilots ensure that ATC is aware of their flight's details, allowing for effective management of air traffic, safety measures, and coordination among multiple flights.

Flight plans also play a critical role in providing situational awareness to ATC in case of emergencies, such as needing to reroute due to weather conditions or other airspace restrictions. While in-flight services for passengers, scheduling maintenance checks, and calculating fuel consumption are all important aspects of aviation operations, they do not directly relate to the fundamental purpose of a flight plan as it pertains to regulatory requirements and air traffic management.