Filed vs. Cleared vs. Flown

Every instrument pilot should understand the process of filing, getting a clearance, and then flying an IFR flight plan. But why does it occasionally seem that ATC makes things complicated? Say you've filed a straightforward Point A to B then C. But then you're cleared from Point A to B then to X, Y, Z, and only finally to Point C. Why are these extra fixes in the flight plan? Where did they come from? Why this today instead of an intermediate RNAV fix that you usually get?

Editorial Staff

Tuesday, January 28, 2020 at 12:00 AM ET

Verified

A court has issued a permanent injunction striking down locally created noise and access restrictions at HTO implemented by the town of East Hampton, New York. Friends of the East Hampton Airport/Facebook

Key Takeaways:

IFR flights frequently receive indirect routings and amended clearances, even when filing direct, because the National Airspace System (NAS) constantly adapts to prioritize overall safety and efficiency.
These complex routings are influenced by dynamic factors such as weather (SWAPs), restricted airspace, Temporary Flight Restrictions (TFRs), Letters of Agreement (LOAs) between facilities, and real-time traffic volume and flow management.
Pilots should anticipate route changes, keep charts updated, file specific routes instead of only direct, and carry extra fuel to accommodate potential reroutes.
While initial clearances might seem circuitous, they often simplify once airborne and clear of heavy traffic or specific airspace restrictions, as the system continuously seeks the most efficient path for all aircraft.

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Every instrument pilot should understand the process of filing, getting a clearance, and then flying an IFR flight plan. But why does it occasionally seem that ATC makes things complicated? Say you’ve filed a straightforward Point A to B then C. But then you’re cleared from Point A to B then to X, Y, Z, and only finally to Point C. Why are these extra fixes in the flight plan? Where did they come from? Why this today instead of an intermediate RNAV fix that you usually get?

I actually get this question more than any other. These seemingly indirect routings might look like a lot more work than something simple, but they keep all airplanes moving safely. Sometimes there may not be much the pilot can do differently, but there are a few ways to possibly anticipate and plan the best route without having to redo it 10 times. The overriding key to this, of course, is that everything aviation is constantly changing, including the optimum route needed of you to keep the entire system moving smoothly.