You're flying along in IMC and things are going well, until you realize, the radio seems pretty quiet.

Is there nobody else in the sector you're flying in, or is there a bigger problem? You ask for a radio check from Center, and nothing. Then you try flight service on 122.2 (or the local frequency on your enroute chart). Still nothing. Finally, you resort to guard frequency on 121.5 to see if anyone can hear you. No response.

At this point, it's just you, your plane, a whole lot of white clouds. So what should you do next?

It all boils down to 4 things: letting ATC know your radios failed, flying your route, flying your altitude, and leaving your clearance to shoot an approach.

Letting ATC Know Your Radios Failed

If you can't talk to ATC, how can you tell them your radios failed? It's simple, squawk the lost communication code: 7600. When you do (assuming you're in radar contact), ATC will know that you're probably not going to be talking the rest of the flight. And with that, they can start planning your arrival, as well as keep other aircraft away from you.

So now that you've let ATC know you're out of radio communication, what's next?

Flying The Route

What you do next is laid out in FAR 91.185. But since the FARs aren't that fun to read, we'll make it a little easier.

Choosing the route you fly for the remainder of your flight is based on what ATC has assigned you, in the order of: last assigned from ATC, vectored, expected, and filed.

Last Assigned

The most recent route clearance from ATC always takes priority, and it makes sense. The route that ATC has given you most recently is what they've planned other traffic around, and it's the first thing they'll expect you to do when your radios go dark.

Vectored

If you're being vectored and you lose radios, you can't just keep flying the vector heading into the "wild blue yonder". If you do, eventually you're going to run out of gas (then you'll be squawking 7700, which nobody wants).

So if you're being vectored by ATC to a fix, route or airway, you want to proceed directly to the place ATC is trying to get you when you radios fail.

For example, if ATC is vectoring you to intercept a Victor airway on your route (e.g. "vectors to intercept Victor 123") and you lose your radios, you'll want to do what they were trying to accomplish in the first place. Fly a direct route from the point of radio failure and intercept the Victor airway. Easy enough, right?

Expected

In the case that you haven't been given an assigned route, you should fly the route that ATC has told you to be expected in a further clearance. So when would that happen?

Let's say you're bucking a headwind and you're not going to have as much gas as you want for landing at your destination. So you call up ATC and ask to amend your flight with a new airport. For this example, let's say your original destination was Livermore, CA (KLVK) and you're headed to Eugene, OR (KEUG) for an Oregon Ducks football game.

You decide that Medford, OR (MFR) is a good place to stop for gas, so you call up ATC to change your flight plan to Medford. ATC responds and says "expect direct Medford airport in one-zero minutes."

At this point, you're still on your original planned route to Eugene, but you're expecting to proceed direct to Medford in 10 minutes. If you're unlucky enough to lose your radios in the time between you get the "expect clearance" and when it actually happens, you'll want to follow those instructions. 10 minutes from when ATC tells you, change your route, and proceed direct to Medford.

Filed

In the off chance ATC hasn't assigned you a full route to your destination, your final fall-back is your flight plan.

When would this happen?

If ATC gives you a clearance for part of your route (to get you started in the air), but they can't yet clear you to your final destination, you don't have any instructions from ATC on how to get to from your clearance limit to your destination.

That's where your flight plan comes in. Since your filed flight plan does include your destination, you'll need to follow the route filed in your flight plan.

What Altitude Is ATC Expecting You To Be At?

Now that we've covered the lateral portion of flying in a radio comm failure, it's time to talk altitudes.

If you lose radios, ATC expects you to fly the highest of: the altitude (or flight level) in the last assigned ATC clearance, the minimum altitude for IFR operations, or the altitude (or flight level) ATC has advised to expect in a further clearance.

Let's look at this example.

Say you're flying from Pueblo, CO (KPUB) to Gunnison, CO (KGUC). Your filed route is KPUB FSHER V244 DUFEL KGUC, and you filed 16,000 feet as your planned altitude.

When you call for your clearance, ATC gives you this: "Cirrus 773GP, cleared to the Gunnison airport as filed, climb and maintain 12,000, expect Flight Level 180 10 minutes after departure, departure frequency 120.1, squawk 4145".

You take off and you're climbing to 12,000 on course when your radios fail. At this point, you need to climb to the highest of the assigned, minimum altitude for IFR operations (in this case, the MEA of V244) or the expected altitude.

Looking at the route of flight, you've been cleared to 12,000', the MEA for the route is 16,000 feet, and you've been told to expect FL180 10 minutes after departure. So you pick the highest, which is FL180, and you climb to that (assuming you're 10+ minutes into your flight). If you weren't yet 10 minutes in, you would climb to 16,000, then FL180 when you were.

Leaving Your Clearance And Shooting An Approach

As you approach your destination, you're obviously going to need to land. And there's a couple ways to make that happen.

First, if your clearance limit is a fix from which an approach begins, you should begin your descent and start the approach as close as you reasonably can to your expect-further-clearance time. Or, if you don't have a EFC time, as close as you can to your estimated time of arrival.

But, in many cases, your last fix isn't a fix where an approach begins, like our example of the Gunnison (KGUC) flight.

Since KGUC isn't the initial fix for any of the approaches, you'll need to leave the clearance limit (KGUC) at your EFC time. Where do you go from there? To a fix where an approach for that airport begins.

If you don't have an EFC time, when you reach KGUC, proceed to a fix where an approach begins and start your descent as close as you can to the estimated time of arrival, based on your filed or amended ETA.

From there, you can shoot the approach, land, and call ATC on the phone to let them know you're down.

When You Pop Out Of The Clouds

With all of these rules in mind, what happens if you break out of the clouds into VMC? If you encounter VFR conditions during a radio failure, you should continue the flight under VFR and land as soon as practical.

Keep in mind, however, that the closest airport might not be your best option. If your radio is broken, you're going to need to get it fixed. And picking an airport with maintenance services (if possible) is better than landing at an airport with nothing but a runway and a self-serve gas pump.

Handling A Failure

Complete radio failures are rare, but when they do happen, remember your route is always what's been assigned, vectored, expected, or filed. And for your altitude, it's the highest of the assigned altitude, minimum IFR altitude, or expected altitude for your route.