Written for instrument students and instrument-rating candidates — the folks who'll actually get asked this on the oral.
You're in the soup at 6,000 feet, hand-flying a V-airway, when you realize Center has gone quiet. Too quiet. You call. Nothing. You try again, check the volume, swap to the standby radio, key the mic on the number two. Still nothing. Congratulations — you've just walked into the single most-tested scenario in instrument flying: two-way radio communications failure, governed by 14 CFR 91.185.
Here's the good news your CFII probably already told you: the FAA wrote the script for you. Your only job is to know it cold, because a cloud layer is no place to be flipping through the FAR/AIM. Let's walk through it the way we would at the whiteboard.
First question: are you actually in the clouds?
Before you touch a single lost-comms procedure, answer one thing — VMC or IMC?
91.185(b) says if the failure happens in VFR conditions, or if you encounter VFR conditions at any point afterward, you continue under VFR and land as soon as practicable. That rule trumps everything else in the section.
This is the step students blow right past. They lose comms in clear air, the adrenaline hits, and they start reciting the IFR script — when the reg just wants them to stay visual, find a field, and land. If you pop out of a layer thirty miles from the airport, you're done with the IFR game. Land somewhere sensible.
And notice the exact wording: "as soon as practicable," not "as soon as possible." Practicable means reasonable. You are not required to dive for the first cow pasture with a windsock. You get to use judgment — pick a suitable airport, weigh the weather, and get on the ground without dragging it out for two hours.
If you're genuinely stuck in IMC, then — and only then — you move to 91.185(c).
Squawk, then fly the plan
In the first few seconds, squawk 7600. That's the transponder code that lights you up on every controller's scope as a comms failure, and it's what starts the machinery on the ground to protect your airspace.
Then fly the plan. Under 91.185(c), the reg answers two questions, and it answers them independently: what route do I fly, and what altitude do I hold?
Route: fly A-V-E-F
For the route, you fly the first of these that applies, in order:
- A — Assigned: the route in your last ATC clearance.
- V — Vectored: if you were being radar vectored, fly direct from the point of failure to the fix, route, or airway named in that vector clearance.
- E — Expected: if you had no assigned route, fly what ATC told you to expect in a further clearance.
- F — Filed: if none of the above applies, fly the route you filed.
Most of the time you're simply humming along on your assigned route, so the answer is "keep flying what you were cleared for." The V-E-F rungs are there for the messier cases — you got pulled off onto vectors, or you were still waiting on a clearance amendment when the radios quit.
Altitude: fly the highest of three
Altitude gets its own rule, and the memory aid is MEA — a fitting pun, since terrain clearance is the entire point. For each route segment, you fly the highest of:
- M — Minimum: the minimum IFR altitude for that segment (think MEA on the chart).
- E — Expected: the altitude ATC told you to expect in a further clearance.
- A — Assigned: the altitude in your last clearance.
The word that matters is highest, and the phrase that matters is for the route segment being flown. If you're assigned 5,000 but the next segment's minimum altitude is 8,000, you climb to 8,000 for that stretch — terrain doesn't care what your last clearance said. Cross onto a segment with a lower minimum and your assigned or expected altitude may take over again. Segment by segment, you're asking the same question: of the three numbers that apply right here, which is highest?
When do I leave the clearance limit and come down?
This is the part that ties people in knots, so slow down with me.
Your clearance limit is the fix you were cleared to — usually your destination airport. What 91.185(c)(3) really cares about is timing. It does not want you showing up early and dropping into an approach while ATC is still holding traffic underneath you.
If your clearance limit is a fix where an approach begins (an initial approach fix, or the destination airport with an approach): begin your descent and approach as close as possible to your Expect-Further-Clearance (EFC) time, if you were given one. No EFC? Then begin as close as possible to your ETA, figured from your filed or amended flight-plan estimate. Arrive early and you hold until it's time.
If your clearance limit is not a fix where an approach begins (say, an en route VOR): leave that limit at your EFC time if you have one, or upon arrival over it if you don't, then proceed to a fix where an approach does begin and time your approach to your ETA.
The theme under both cases is identical: fly predictably, on the timing ATC can anticipate, so the controllers can keep everyone else clear of you.
Why bother, in the age of ADS-B and cell phones?
Fair question. A true lost-comms-in-IMC event is genuinely rare now. Controllers see you on ADS-B, plenty of pilots have simply pulled out a phone and called the facility, and often ATC will clear a path without you doing a thing. So why memorize the script?
Because 91.185 is a contract. ATC protects the airspace on the assumption that you're flying it. The moment you improvise, you and the controller are working from different playbooks, and that's exactly when metal gets close to metal. Fly the reg so everyone's on the same page. And keep in mind your emergency authority under 91.3(b) is always in your back pocket — if the situation isn't covered by 91.185, or a deviation is plainly safer, you're the pilot in command. Use good judgment.
The takeaway
Lost comms feels like an emergency right up until you remember the FAA already did the hard thinking. Ask VMC or IMC first, and stay visual if you can. Stuck in the clouds, squawk 7600, fly the route A-V-E-F, hold the highest applicable altitude segment by segment, and time your approach to your EFC or ETA so ATC can protect you.
This is a near-guaranteed oral-exam topic, so drill it until you can sketch the whole thing on a napkin. The ASA Instrument Oral Exam Guide runs these scenarios the way an examiner actually asks them, and a lot of instrument students keep the AVEF/MEA flow written on a Kneeboard so the script is right in front of them the first few times they fly it under the hood.
For more resources to support your instrument training, visit NorthstarVFR.com.