Updated: Nov 20
Communications with air traffic control is one of the basics of the IFR structure. But communications, just like any other system, are prone to failure. What do you do if you lose contact with ATC on an IFR flight?
It starts with a clearance…
Let’s look at an example, let’s say you’re planning a flight, between Morgantown West Virginia, and Hagerstown, Maryland.
Your flight plan has you departing Morgantown Airport, proceeding to your first fix, OTOWN, then going direct to the Indian Head VOR, where you’ll join victor 268, to the Hagerstown VOR and on to your destination.
Lost communications planning starts from the moment you get your clearance, even if it’s not obvious how.
Take a look at the clearance you got from ATC.
You’re cleared to Hagerstown airport. Via OTOWN, Indian Head, victor 268, Hagerstown. You’re told to maintain 5000, and to expect 7000 feet 10 minutes after departure. Your departure frequency is 121.15, and our squawk is 3217.
So how does this information tell you what to do if you lose your radios? It turns out that you have everything you need to continue a flight if the worst happens, like loosing radio contact right after departure.
After departure the worst happens
When taking off, take note of the time of your departure, today it’s 26 minutes after the hour. Now imagine this: After you’ve cleared the field, tower hands you off to departure, and when you switch over to 121.15, your radio fails. You’ll start troubleshooting in a bit but for now, let’s assume that this radio is not coming back on, while you’re entering IMC.
The first thing to do is fly the airplane. you’ve already programmed the autopilot to fly to the first fix, OTOWN, and climb to 5000 feet. This was the altitude we were assigned in your IFR clearance.
Following lost comms procedures
Now that you’ve got aviate and navigate out of the way, what can you do about communicate. Obviously, the radio being out, doesn’t mean that the transponder is not working. You’ll want to squawk 7600 right away!
7600 let ATC that you’re having radio issues, and they will expect you to follow lost comms procedures. That way even though they can’t issue instructions, they’ll know what to expect from you.
But, what does ATC expect from you? In your clearance, you were given two altitudes. One was the assignment of 5000 feet, which you’re currently climbing to. The other was 7,000 feet, the altitude you were told to expect 10 minutes after departing.
When ATC tells you to expect something, they’re not just saying that to get you excited about what’s next, it’s specifically in case you lose communications under IFR. If I tell my daughter she can expect some ice cream, if she doesn’t hear from me soon, she’ll probably go grab the ice cream out of the freezer herself.
It’s the same with IFR pilots who don’t hear from ATC. They’ll do what they were expected to do. In your case, it’s to climb to 7000 feet 10 minutes after departure.
So you’ll fly at 5,000 feet, and once 10 minutes after your departure time, which was 26 minutes after the hour, have elapsed, you’ll climb to 7,000 feet.
Meanwhile you want to think about your options. You’re in IMC right now, but if you were VFR, you could break off your expected flight plan, stay in VFR conditions and find an airport where you could land visually. If it has a control tower you would expect the light gun signals. This is the other thing the 7600 lost comms code will get for you.
This is the best case, find VFR conditions. You should always know where the nearest VFR is and if you have the fuel to fly there.
But let’s say you don’t have VFR conditions nearby. Let’s recap what you’ve done so far. You departed, climbing initially to your assigned altitude of 5,000 feet, along your filed route of flight. You didn’t need a radar vector, but if you had gotten one prior to our comms failure, you would have flown that and proceeded directly to the fix or airway you were being vectored to.
you stayed at 5,000 until 10 minutes after your departure, then climbed to your expected altitude of 7,000 feet. This took you a few miles from the Indian Head VOR.
This is where you’re going to pick up victor 268, Let’s look at the minimum altitudes for this segment of the airway.
You’re in your Cirrus, so we'll assume you can use the GPS MEA of 4,700 feet. you’re currently at your expected altitude of 7,000 feet, so you’ll stay at that since it’s the higher of the two.
But let’s say you were just using VOR to navigate this airway. You’d need to observe the higher MEA of 12,000 feet, and once joining the airway, climb to that altitude. The point here is that when there is more than one possible altitude, like an expected altitude and an MEA, we always take the highest one in lost comms. Incidentally this the lowest ATC would have you fly this part of the route anyways if you were still in radio contact.
So how does it all end?
Now hopefully you’ve regained contact with ATC or found VFR conditions, but if you haven’t, how does this whole thing end? Again let’s look to your clearance.
The “C” in craft is our clearance limit. 99% of the time, this is your destination airport, which is the case here. So can you just pull up an approach and land? Sort of. The regs say in 91.185 to proceed to your clearance limit, and then proceed to a fix from where you can begin an instrument approach to land, timing it so that you arrive as close as possible to the ETA you filed in your flight plan.
Now let’s get a little realistic. If you arrive at Hagerstown a little on the early side before our ETA, no one at air traffic control is looking at a clock making sure you’re delaying your approach until the right time. ATC doesn’t want you circling in IMC above the airport any more than you want to. You can exercise your judgment, and if necessary, your emergency authority, to commence an approach upon arrival. Worried about CYA? Switch your squawk to 7700 for an emergency, and do the paperwork once you’re safely on the ground.
Take a look at the ILS for runway 9 approach. The localizer is almost lined up with your course, so if the conditions permit, which is a big if, remember without comms you may have no way of getting weather information, you’ll plan this approach.
What about altitudes? you’re at the MEA for this airway, and you should stay at that altitude until you can use the minimum safe altitude for this approach. It’s 4,000 feet within 25 miles of the Martinsburg VOR. So you’ll go no lower than that until established on the approach. You’ll head to the initial approach fix, COVUK, and fly the ILS down to land. Once on the ground you’ll want to get in touch with the tower by phone or other means to get tell them about the whole incident.
Now, let’s go back a bit and say that you were actually able to regain communications while you were still en route to Hagerstown. Approach tells you at some point to expect the ILS runway 9. Again that word "expect". It means you haven’t been instructed to do anything different, but in the event of a lost comms at this point, this is the approach you should execute just as we did in the prior example.
Next ATC tells us next to proceed direct COVUK, the initial approach fix, and then tell you to get ready to copy holding instructions.
They tell you to “hold west of the COVUK intersection as published. Expect further clearance at 1630 Zulu. Time now 1620 Zulu.”
Notice the magic word expect again. It’s another lost comms item. The time is now 1620 zulu. You’ll hold and wait for further clearance. If you lost comms here, you’d have to stay in the hold until 1630 zulu, this is the time you were told to expect further clearance. Sometimes this is abbreviated EFC, our EFC time is 1630 zulu. And at that time you can start your approach on the ILS.
This is a rundown of the lost communications rules laid out in FAR 91.185. The thing to understand about lost comms in IMC is that it is not anybody’s best case scenario. The regs are designed so that when ATC can’t communicate with you, you at least stay predictable, allowing them to accommodate traffic around you.
Have a look at our VFR Radio Communications Course if you're interested in more details on this topic.