IFR Route Clearances

There are two fundamental types of IFR route clearances. The IFR route we all hope for is “cleared as filed.” The other, an amendment to your planned IFR route, can cause problems. Let’s look at both types and see how they impact your flight.

As Filed is Music to Your Ears

When you call on the radio for your pre-departure route clearance, what you would most like to hear after your call sign is, “cleared as filed.” Not only is that type of clearance easy to copy, it also means you won’t have to re-calculate your flight’s fuel consumption and flying time.

Essentially, ATC has agreed your planned route meshes with their plan for air traffic flow. While ATC takes your aircraft’s performance and fuel load into account, traffic flow is the ultimate driver in determining whether you will able to fly your plan. If your plan does not fit into the overall traffic flow, then you are going to get an amendment to your route of flight.

Look Out, Here is Comes

When you hear the person delivering your route clearance say, “I have a full route read back. Advise when ready to copy,” you can expect some changes to your planned route of flight. This might present two problems.

First, you have to be ready to accurately write the changes to your route. Second, you have to understand those changes. Third, you have to judge whether you can tolerate those changes. I’ll get to the part about writing and understanding in a moment. Let’s talk, right now, about tolerance.

All-Consuming Idea

When flying and amended route, your first consideration should be fuel consumption. While most route amendments delivered by ATC are usually minor deviations off your planned route of flight, some can involve long detours.

For example, let’s say your originally planned route of flight took you through a charted Military Operating Area (MOA) that was scheduled to be inactive. Prior to departure, the Air Force decided it wanted to use the MOA during the time of your transit. ATC will amend your pre-departure clearance with a route that takes you around the MOA.

Depending on how you originally filed, the amended route may take your flight on a detour of a few miles. Or, the detour may be long enough that the extra miles will eat into your fuel reserve. It falls on your shoulders to examine the re-route, calculate the extra fuel burn, and make a go/no-go decision before you turn a wheel. Fortunately, time is on your side.

Time is On Your Side

The beauty of a pre-departure clearance is, it gives you time to decide how to proceed before you start burning gas. If the re-route won’t work for you, you can decide to:

1. Refuse the routing and file a new route that will work.
2. Take on additional fuel.
3. Cancel the flight and try another time.

The important point is this. Only you know whether a route of flight will work for you and your aircraft. ATC primary goal is to fit your airplane into the flow of traffic. While both the FAA and you want to have a safe flight, as pilot-in-command, you are ultimately responsible for determining whether ATC’s interests match your interests.

For more about how to copy and understand route amendments, check out Clearance Magic. Clearance Magic is a complete, learn-by-doing program for copying ATC clearances with ease and accuracy, every time.