ATC Light Gun Signals: What They Mean (and How to Use Them Without Panic)
- wifiCFI
- 5 days ago
- 4 min read
You’re taxiing out, ready to go, and suddenly your radio goes silent. Or you’re in the pattern and realize you can hear ATC, but they can’t hear you. Or your headset dies at exactly the wrong time.
This is where ATC light gun signals stop being a trivia question and become a real-world tool. They’re simple, standardized, and effective—if you actually remember what they mean and know how to respond.
This pilot-focused guide covers what the signals are, what they mean in the air vs. on the ground, how to acknowledge them, and a few practical “don’t mess this up” tips.
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When light gun signals come into play
ATC uses a light gun when:
you have radio failure (NORDO),
there’s frequency congestion and they need to communicate quickly,
or in rare cases, during equipment issues or emergencies.
Most commonly: towered airport + aircraft not communicating.
Light signals are directed at a specific aircraft, so it helps to:
look for the tower,
rock your wings (in the air) or flash taxi/landing light (on the ground) to show you’re paying attention.
The light colors and what they mean
Light gun signals come in three colors:
Green
Red
White
And each color can be:
Steady (continuous)
Flashing (repeating)
That’s it—six signals total.
The tricky part: meanings change depending on whether you’re in the air or on the ground.
Light gun signals chart (pilot-friendly)
In the air
Steady Green: Cleared to land
Flashing Green: Return for landing (enter/continue pattern)
Steady Red: Give way / continue circling (do not land)
Flashing Red: Airport unsafe, do not land
Flashing White: Not used (in the air)
Alternating Red and Green: Exercise extreme caution (rare, but memorable)
On the ground
Steady Green: Cleared for takeoff
Flashing Green: Cleared to taxi
Steady Red: Stop
Flashing Red: Taxi clear of runway / do not enter runway
Flashing White: Return to starting point on the airport
Alternating Red and Green: Exercise extreme caution
If you take nothing else away:
Steady green = “cleared” (land in the air, takeoff on the ground)
Steady red = “stop / don’t land”
Flashing green = “move” (taxi or come back around)
Flashing red = “danger / runway problem”
Flashing white = “go back” (ground only)
How to acknowledge a light gun signal
ATC needs to know you saw it.
In flight:
Rock your wings (a clear, deliberate wing rock)
On the ground:
Flash your landing light or taxi light (if equipped)
Some pilots will momentarily turn the light on/off if it’s a steady-beam switch. Keep it obvious.
Avoid “acknowledging” by:
weaving on the taxiway,
rapid strobe flipping,
anything that looks like you’ve lost control.
Make it unmistakable and calm.
Practical tips for actually spotting signals
1) Know where the tower is—before you need it
If you go NORDO, the tower becomes your “radio.” Identify its location early, especially at unfamiliar airports.
2) Don’t stare inside while NORDO in the pattern
A radio failure tends to create checklist tunnel vision. Fly the airplane, keep spacing, and scan for the signal.
3) Use standard predictable behavior
ATC is trying to fit you into traffic:
fly standard pattern entries,
keep speeds consistent,
avoid surprise shortcuts.
Light signals are simple, but traffic sequencing still matters.
The “what do I do now?” scenarios
Scenario A: You’re holding short and NORDO
Look to the tower.
If you get flashing green: taxi is authorized (not takeoff).
If you get steady green: cleared for takeoff.
If you get flashing red: clear runway / do not enter.
If you get steady red: stop.
Common mistake: taking off on a flashing green. Flashing green on the ground is taxi, not takeoff.
Scenario B: You’re on final and the radio dies
Look for:
steady green (cleared to land)
steady red (do not land—continue circling)
If you don’t see a signal:
stay predictable,
consider going around if uncertain,
and keep scanning for the light.
Scenario C: You see flashing red on final
That’s ATC saying: airport unsafe, do not land. Go around, climb, and remain in a safe area while looking for further instructions/signals.
Scenario D: Alternating red and green
This is the “something’s weird” signal: exercise extreme caution. Think:
vehicle on a runway,
runway incursion risk,
unusual hazard,
emergency activity.
Slow down mentally and physically. Don’t assume clearance for anything unless you get a clear steady green appropriate to your situation.
Safety precautions and good habits
Don’t wing it—have a NORDO plan
At towered airports, especially in busy airspace, have a quick plan:
“If radios fail, I’ll remain in the pattern at X altitude, look for light signals, and keep spacing.”
Don’t block the runway waiting for a signal
If you’re unsure:
stay clear,
return to a safe spot if needed,
keep looking to the tower.
If you can receive but not transmit, say so
If you can hear ATC but your mic is dead:
try another mic/headset jack if available,
use handheld radio if you have one,
squawk 7600 if appropriate and workload permits.
(Procedures vary; follow your training, regulations, and ATC expectations. The key is: don’t create ambiguity.)
A memory trick that works
Green means go
Red means stop
White means “go back”
Flashing means “not the final clearance” (except taxi/return for landing)
Steady means “this is the clearance” (land or takeoff)
And remember the big one:
Steady green changes meaning depending on where you are:
Air: cleared to land
Ground: cleared for takeoff
Wrap-up
Light gun signals are rare—until they aren’t. If you review them once in a while and rehearse “radio fails in the pattern,” they become a calm, simple fallback instead of an adrenaline event.
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