What Are All Six Light Gun Signal Meanings for Aircraft in the Air, and How Do You Acknowledge Them?

Why Light Gun Signals Still Matter in a Modern Cockpit

In an era of digital avionics and always-on radio communication, it might be tempting to treat light gun signals as a relic of aviation history. Your examiner will not see it that way. The Aeronautical Information Manual (AIM), in its Airport Operations chapter covering Light Gun Signals, makes clear that every certificated pilot must understand these signals completely. A radio failure can happen to any pilot at any time, and a busy controlled airport does not stop operating just because your comm radio goes silent. The light gun is the tower controller's direct line to you, and your ability to read and respond to it correctly is a genuine safety skill — not a trivia question.

What makes this topic particularly dangerous on the checkride is that most student pilots memorize only the two or three most common signals and assume that will be enough. It is not. Examiners know this, and they will probe until they find the edge of your knowledge. The goal of this post is to push that edge out far enough that there is nothing left to find.

The Six In-Flight Light Gun Signals, One by One

There are exactly six light gun signals that apply to aircraft in flight, and you need to know all of them cold — not just the color, but the specific clearance or instruction each one conveys.

• Steady green — Cleared to land. This is the one most pilots know, and it means exactly what it sounds like: you are authorized to continue your approach and land.
• Flashing green — Return for landing. More precisely, you are cleared to approach, but you have not yet received a landing clearance. Think of it as an invitation back into the pattern when you are somewhere in the vicinity of the airport.
• Steady red — Give way to other aircraft and continue circling. This is a hold signal. Something else has priority on the runway or in the pattern, and you need to maintain your orbit until the situation clears.
• Flashing red — Airport is unsafe, do not land. This is an urgent warning. There may be a disabled aircraft on the runway, construction equipment, or another hazard that makes landing impossible. Do not descend.
• Alternating red and green — Exercise extreme caution. This signal does not give you a specific instruction; it is a warning that something hazardous or unusual is happening. Stay alert and proceed carefully.
• Flashing white — This one belongs on a separate line because it is the signal that trips up the most students. Flashing white means return to your starting point on the airport — but here is the critical detail that almost everyone gets wrong: flashing white has no meaning for aircraft in the air. It is a ground-only signal. If you tell your examiner that flashing white means something to an aircraft in flight, you have just demonstrated a gap in your knowledge that could fail the checkride.

That last point deserves emphasis. Confusing flashing white with flashing green — or assuming it means return for landing — is one of the most common errors examiners encounter on this topic. The two signals look completely different in color and pattern, but students who have not drilled the full list tend to blur them together under pressure.

How to Acknowledge a Light Gun Signal

Reading the signal is only half the task. The AIM is explicit that pilots must acknowledge receipt of a light gun signal so the controller knows the message was received. Failing to acknowledge is like reading a text message and leaving the sender with no idea whether you saw it — except in this case, the consequences are measured in runway incursions and midair conflicts.

The acknowledgment method depends on the time of day. During daylight hours, rock your wings to confirm you have received and understood the signal. At night, blink your landing light — or, if your aircraft is not equipped with a landing light, your navigation lights. The controller is watching for your response, and providing it quickly and clearly is part of professional airmanship.

This is a detail many students forget entirely. They know the signal meanings but have never thought about what happens next. On the oral exam, your examiner will almost certainly follow up the signal question with: how do you let the tower know you got the message? Have a clean, confident answer ready.

After the Landing: Your Lost-Comm Responsibilities Do Not End on the Runway

Suppose you receive a steady green, rock your wings, land successfully, and taxi to the ramp — all without a functioning radio. Are you done? Not quite. Once you have parked the aircraft, you are expected to contact the tower by telephone as soon as practicable to advise them of the situation. This step exists so that ATC can close the loop on the communication failure, update their records, and investigate whether there is a broader issue with your equipment or their frequencies.

Skipping this step is a procedural error that some students do not even know they are making. The oral exam tests whether you understand the complete sequence of a lost-comm event — from the first light gun signal you receive in the air, through your acknowledgment, through your landing, and all the way to the follow-up phone call on the ground. Know every step, and you will leave no room for doubt in your examiner's mind.

Light gun signals are the kind of topic that separates a well-prepared candidate from someone who studied only the highlights. If you want to practice questions like this in a realistic oral exam format, try SimulatedCheckride.com.