In our Ask a Pilot series, pilot Spencer Marker answers one of your aviation-related questions each week (picking up this week after a short baby-related break). See past installments here and submit your own to Whitney@johnnyjet.com.
Hey Spencer, who decides the route? ATC, the airline or the pilot?
Hey John! Thanks for this awesome question. There are a lot of factors that go into deciding which route an airplane will take as it makes its journey. And not to skip ahead, it’s truly a collaborative effort between the pilots, the airline’s dispatchers and ATC as to which path the flight will ultimately take. That being said, there are several factors that funnel into the decision, and I’m happy to discuss them now.
To most passengers, it seems an airplane’s journey begins the moment it leaves the gate. And while that’s physically true, the work to dispatch a single flight begins hours earlier with a group of airline employees called dispatchers. These behind-the-scenes members of an airlines are primarily tasked with flight planning and dispatching the flight. This includes coordinating with Meteorology for any weather issues, and Maintenance Control for any inbound maintenance issues, among other concerns. Dispatchers produce a series of documents that make up a pilot’s flight release, or paperwork. You may have seen pilots with a large stack of papers at the gate; that is their release. No commercial airplane can be dispatched to carry passengers without one.
Contained in the release is the airplane’s route. This route was selected by the dispatcher based first on standard routes selected by the airline for efficiency. For instance, the standard route for a flight from Atlanta to Newark may include flying over Greensboro, NC, Norfolk, VA, and Philadelphia, PA, before getting to Newark. This is the route most often filed by the company if there is no reason to route the aircraft differently.
But the dispatcher may choose to deviate from the standard route if weather or operational issues require it. Reasons for deviation can include thunderstorms, areas of turbulence and high winds at altitude. If a flight’s standard route takes it across an area of thunderstorms, the dispatcher may opt to reroute the flight around them. Areas of turbulence can be avoided similarly. Finally, if the flight is due to encounter strong headwinds, the dispatcher may choose to route the flight on a longer route based on mileage, rather than have it fight strong headwinds to its destination. Conversely, if the flight can take advantage of tailwinds, the dispatcher may change the route in order to do so.
When the dispatch release is in the pilot’s hands, the pilot must review and become familiar with all the aspects of the flight. This includes reviewing the route. If the pilot notices an issue with the route, like an area of rapidly developing weather, he or she must contact the dispatcher and work to resolve the issue. If both agree, the dispatcher will amend the release and file a new route with ATC before the flight departs.
Once the flight is underway, pilots are continuously reviewing the route. I often joke that pilots are the only professionals that are paid by the hour but still want to go fast and take shortcuts along the route! Often, pilots will request shortcuts from ATC if they think that they can save time or fuel. We call this requesting direct, or to fly directly to a fix or waypoint. Pilots can also modify the route if they need to avoid weather. If a pilot requests a heading change to avoid thunderstorms, we call this deviating. The understanding is that the route change is temporary, so a heading is requested to avoid weather, and the pilot will join back to the planned route as soon as they are able.
If the weather is significant enough, the pilot will ask ATC to deviate away from it, then coordinate with their dispatcher to find an alternate route. Since the longer an airplane flies, the more fuel it consumes, the route must be coordinated to ensure that adequate fuel is on board the aircraft.
Air traffic control can also modify a flight’s route. Sometimes this change occurs before a flight departs the gate. This happens when the route a dispatcher files is different from the ATC’s preferred route. The change can be small, with just a couple new fixes, or large, requiring coordination with dispatch and additional fuel planning. We call this an ATC reroute.
Once a flight is underway, ATC can change the flight’s route by offering the pilots a more direct path to their destination, a change to avoid weather, or a new arrival time at their destination. When a plane is flying into a congested airport, like in New York or Los Angeles, ATC will change an airplane’s arrival routing to better manage the flow of traffic.
Again, as with pilot-modified route changes, if ATC issues a large route change, a pilot must coordinate with the flight’s dispatcher to ensure there is adequate fuel to fly the new route.
To sum up
Thanks for that great question, Johnny. The route a flight ultimately takes is a well-coordinated effort among dispatch, the pilots and ATC. Dispatchers bear the brunt of the responsibility, as they are entrusted with planning the flight and coordinating any route changes the pilots or ATC come up with. Nonetheless, through careful coordination between these groups, flights are able to criss-cross the country safely and comfortably.
Thanks again for the question! Have you been on a flight with an odd route? Share in the comments below! And if anyone has a burning aviation question or something you would like cleared up, drop us a line at Whitney@johnnyjet.com to get your question featured in an upcoming Ask a Pilot column.