You are at 8,000 feet in solid cloud. You key the mic to check in with approach control. Nothing. You try again. Static. You switch frequencies, toggle the volume, check the headset jack. Dead air. The airplane is flying fine. The weather is not. And the one link between you and the system keeping you separated from mountains, airliners, and other traffic just went silent.

Lost comm — pilot shorthand for the failure of two-way radio communication — is one of those emergencies that feels manageable until you actually think through what it means. You cannot hear ATC. ATC cannot hear you. You are now flying an invisible aircraft through controlled airspace, and the entire system needs to predict what you will do next.

The good news: there is a plan. It is old, it is elegant, and it works. But only if you know it.

Squawk 7600: The Silent Alarm

The first action is automatic for any trained pilot. Dial 7600 into the transponder. This four-digit code is aviation’s universal “I can’t talk to you” signal. The moment a controller sees 7600 on their radar screen, they know exactly what is happening. Your data tag changes. Procedures activate. Other aircraft are kept clear.

In VFR conditions — clear skies, good visibility — the procedure is simple. Stay VFR, land as soon as practicable, and sort it out on the ground. If you can see the airport, fly to it, look for light gun signals from the tower (steady green means “cleared to land”), and put the airplane on the pavement. The radio is a convenience in VFR. You can fly without it.

IFR — flying in clouds on instruments — is where lost comm becomes genuinely complicated. You cannot see other traffic. You cannot see terrain. And you cannot deviate from your route without telling someone, because the entire system is built on knowing where every airplane is going next.

The AVE-F Rule: Where to Go

The FAA’s lost-comm procedure for IFR flight lives in regulation 14 CFR 91.185, but pilots compress it into a single mnemonic: AVE-F. This tells you what route to fly, in order of priority:

A — Assigned. Fly the route ATC last assigned you. If approach told you “fly heading 270,” keep flying heading 270.

V — Vectored. If you were being radar-vectored, fly to the fix or route that ATC was vectoring you toward — the place where the vector was obviously leading.

E — Expected. Fly the route ATC told you to expect. Controllers often say “expect the ILS Runway 28 approach” — that expectation becomes your plan.

F — Filed. If none of the above apply, fly your filed flight plan route. This is your last resort, and it works because ATC has a copy of your flight plan and can predict your path.

The Altitude Rule: How High to Fly

For altitude, the regulation uses a similar hierarchy. Fly the highest of: the altitude assigned in the last ATC clearance, the altitude ATC told you to expect, or the minimum en route altitude (MEA) for the segment you are on. The logic is vertical separation — by flying the highest applicable altitude, you stay above terrain and above aircraft flying at lower assigned altitudes.

The timing rule is equally specific. If you arrive at a clearance limit (usually the destination airport) before your expected approach time, hold there until that time, then begin the approach. If no expected time was given, proceed upon arrival. The system assumes you will fly the approach at a predictable time, so ATC can clear the airspace below you.

Light Gun Signals: The Tower’s Backup Language

When you reach the airport without a radio, the control tower communicates using a light gun — a focused beam of coloured light aimed directly at your aircraft. The signals are universal:

Steady green: cleared to land. Flashing green: return for landing (you are approved to enter the pattern). Steady red: give way, continue circling. Flashing red: airport unsafe, do not land. Alternating red and green: exercise extreme caution.

You acknowledge by rocking your wings during the day or flashing your landing light at night. It is a system designed in the 1940s. It still works.

The System Bends, Not Breaks

Lost comm procedures exist because the architects of the air traffic system understood a fundamental truth: radios fail. Electrical systems short out. Headset plugs come loose. Frequencies get congested. The system was designed from the beginning with a fallback — a set of rules that let a silent airplane navigate safely to the ground without a single spoken word.

Modern GPS, glass cockpits, and digital communications have made total comm failure rarer than ever. Many aircraft now carry multiple independent radios, satellite communication links, and ADS-B transponders that broadcast position regardless of radio status. But the 7600 squawk code and the AVE-F mnemonic endure — because the next electrical failure is always one corroded wire away.

For student pilots, lost comm is a checkride question. For instrument pilots, it is a procedure to know cold. For passengers, it is a reassurance: even if the radio dies, the airplane does not. There is always a plan, always a procedure, always a way down.

Sources: FAA 14 CFR 91.185, Aeronautical Information Manual (AIM) Chapter 6, AOPA Lost Communications Procedures Guide, Boldmethod