Light-Gun Signals & Lost Comms

When the radio quits

Definition

A radio failure isn't a disaster — you have procedures. First, recognize it: you stop hearing replies, or a normally busy frequency goes silent. Then work the problem.

Explanation

Run the quick checks — turn the volume up, confirm the right frequency, make sure your headset and mic are plugged in, and check the push-to-talk isn't stuck; try your second radio or the last frequency that worked. Set the transponder to 7600 so ATC knows you're NORDO (no radio). And learn how to answer a controller without words: by day you rock your wings, by night you flash your landing or navigation lights.

Step	What to do
Recognize it	No replies, or a normally busy frequency goes silent. Suspect a lost-comms (NORDO) situation.
Quick checks	Volume up, correct frequency, headset/mic plugged in, push-to-talk not stuck; try COM2 or the last frequency that worked.
Squawk 7600	Set the transponder to 7600 so ATC and radar see you're NORDO.
Acknowledge by day	Rock your wings to acknowledge a light-gun signal.
Acknowledge by night	Flash your landing light or navigation lights to acknowledge.

Why it matters

A calm, methodical response to a dead radio — squawk 7600, look for light guns, keep flying the airplane — turns a scary moment into a routine one.

A DPE might ask

Your radio goes quiet — what's your first response?
How do you acknowledge a controller's light-gun signal?

AIM 6-4 / 4-2 — Two-way radio communications failure

Light-gun signals

Definition

When you have no radio, the tower talks to you with a light gun — a focused beam of colored light. Each color, and whether it's steady or flashing, has a specific meaning, and the meaning changes depending on whether you're on the ground or in the air.

Explanation

Steady green clears you (takeoff on the ground, landing in the air). Flashing green means cleared to taxi on the ground, or return for landing in the air. Steady red means stop on the ground, or give way and keep circling in the air. Flashing red means taxi clear of the runway on the ground, or the airport is unsafe — do not land — in the air. Flashing white means return to your starting point on the airport (ground only). Alternating red and green means exercise extreme caution.

Figure 14-42. Light gun signals. — Figure 14-42 · FAA-H-8083-25C, Pilot's Handbook of Aeronautical Knowledge (p. 359)

Why it matters

A light-gun signal may be the only way the tower can reach you. Reading it right — especially 'flashing red in flight: do not land' — is a genuine safety skill.

A DPE might ask

What does a steady green light mean in flight? On the ground?
You're on final and get a flashing red — what does it mean and what do you do?

AIM 4-3-13 — Traffic control light signals

Practice: match the signals

Definition

Now drill it. Match each light-gun signal to what it means — first for aircraft in flight, then on the ground. Tap a signal, then tap its meaning; correct pairs lock in.

Explanation

Recognition needs to be automatic, because when you actually see a light gun you won't have time to look it up. Play both boards — in flight and on the ground — until you can match them without hesitating. Notice how the same color means related but different things depending on where you are.

Figure coming soon diagram: lightgun.game

Why it matters

Speed matters: a light gun is used precisely when there's no time for the radio. Drilling the pairs builds the instant recall you'd need for real.

A DPE might ask

Without looking, what's flashing green in flight?
What's the difference between steady red on the ground and in the air?

AIM 4-3-13 — Traffic control light signals

Lost comms at a towered field

Definition

At a towered field you normally need a radio, so a failure means you switch to the light-gun plan: let ATC find you, watch for the light, and comply.

Explanation

Squawk 7600 so radar tags you as NORDO. Approach the field and watch the tower for a light-gun signal — then comply and acknowledge (rock the wings by day, flash the lights by night). Join the flow carefully, expect a steady or flashing green to land, and keep your eyes outside. This is the VFR light-gun procedure (14 CFR 91.126/91.129); the IFR lost-comms route (91.185) is a separate, later topic.

At a towered field	What to do
Squawk 7600	Set 7600 on the way in so radar tags you as NORDO.
Watch the tower	Look for a light-gun signal from the tower and comply.
Acknowledge	Rock the wings (day) or flash the lights (night) to show you got it.
Join carefully	Enter the flow, keep your eyes outside, and expect a steady or flashing green to land.
It's VFR light-gun	This is the VFR light-gun procedure (91.126/129) — not the IFR lost-comms route (91.185).

Why it matters

Arriving NORDO at a towered field is manageable when you know to squawk 7600 and look for the light — panic and unpredictability are the real hazards.

A DPE might ask

You arrive at a towered field with a dead radio — walk me through it.
What code do you squawk, and what are you looking for?

AIM 4-2 / 4-3 — Towered-field lost comms

Lost comms at a non-towered field

Definition

At a non-towered field, a radio was never required in the first place — so a failure barely changes your plan. You were already responsible for seeing and avoiding.

Explanation

Fly the standard pattern: enter on the 45° to the downwind, fly predictable legs, and use the wind indicators to pick the runway. Scan constantly and give way, because others may also be no-radio and no one is announcing for you. Then land normally. The whole non-towered system is built on see-and-avoid, which is exactly what you fall back on.

At a non-towered field	What to do
No radio required	Two-way radio isn't legally required at a non-towered field, so a radio failure isn't an emergency.
See and avoid	Fly heads-up: scan constantly and give way — no one is announcing for you.
Fly the standard pattern	Enter on the 45° to the downwind and fly a normal, predictable pattern (see Traffic Patterns).
Expect NORDO peers	Others may be no-radio too; don't assume anyone hears you or is heard.
Land normally	Pick the runway from the wind indicators and land.

Why it matters

Knowing that a radio isn't legally required at a non-towered field keeps a comm failure from feeling like an emergency — you already have the skills you need.

A DPE might ask

Is a radio required at a non-towered field?
How does a radio failure change your arrival at a non-towered field?

AIM 4-1-9 — Non-towered operations

Emergency codes & wrap

Definition

Finally, the transponder emergency codes — three numbers worth memorizing cold — plus the emergency frequency.

Explanation

7500 means unlawful interference (a hijack). 7600 means lost communications. 7700 means a general emergency. A common memory hook: '7500 taken alive, 7600 nix comms, 7700 going to heaven.' And 121.5 is the emergency 'guard' frequency you can call on (it's also what an ELT transmits on — from the Regulations module). Your normal VFR code, by contrast, is 1200.

Code	Meaning
7500	Unlawful interference (hijack) — "taken alive."
7600	Lost communications — "nix comms."
7700	Emergency — "going to heaven."
121.5	The emergency voice "guard" frequency (also what an ELT transmits on — see Regulations).
1200	The standard VFR code (not an emergency) — your normal squawk.

Why it matters

In a real emergency you won't have time to look these up — 7700 and 121.5 for an emergency, 7600 for a dead radio, are instant-recall items.

Common error

A common mix-up is which emergency code to squawk. If only your radio fails, that's lost communications — 7600 — not the general emergency code 7700. Keep them straight: 7600 for a dead radio, 7700 for an actual emergency.

Your radio quits en route but everything else is fine. What do you squawk?

A DPE might ask

What do 7500, 7600, and 7700 mean?
Radio fails but nothing else is wrong — which code?

AIM 4-1 / 6-4 — Transponder emergency codes