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

Why Light Gun Signals Show Up on Almost Every Checkride

Your designated pilot examiner is not going to let you walk out of the oral without testing your knowledge of light gun signals. This topic sits squarely in the Airport Operations section of the Aeronautical Information Manual, and it checks two things at once: whether you understand radio-failure procedures and whether you have actually memorized all six signals rather than just the one or two you think will come up. Most candidates know steady green means cleared to land. Fewer know all six, and fewer still know the correct acknowledgment procedure and what to do after a lost-comm landing. That gap is exactly where checkrides are failed.

Light gun signals exist because the aviation system needs a reliable backup when radio communication breaks down. Tower controllers are trained to use them, and you are required to recognize and respond to them. The AIM dedicates a full reference section to these signals under Airport Operations, and the FAA considers mastery of this material non-negotiable for the private pilot certificate.

The Six Signals, One by One

There are exactly six light gun signals defined for aircraft in flight, and each one carries a specific, unambiguous meaning. Here they are in the order you should burn into memory.

• Steady green — Cleared to land. This is the one most students know, and it is the signal you are hoping to see on a no-radio approach.
• Flashing green — Return for landing, cleared to approach. You are not yet cleared to land, but the tower is inviting you back into the pattern. Think of it as a preliminary clearance to start the process.
• Steady red — Give way to other aircraft and continue circling. Something is occupying the runway or the approach environment. Stay up, keep the pattern going, and wait for further signals.
• Flashing red — Airport unsafe, do not land. This is a serious signal. Something on or near the airport makes landing hazardous right now. A vehicle on the runway, a gear-up aircraft blocking the threshold, or an emergency in progress could all trigger this signal.
• Flashing white — This one trips up a surprising number of candidates. Flashing white means return to your starting point on the airport, and here is the critical detail: it is a ground-only signal. It has no defined meaning for an aircraft in the air. If you are in flight and you see flashing white, the signal simply does not apply to you. Many students mistakenly associate flashing white with a return-for-landing clearance, confusing it with flashing green. Do not make that swap on your checkride.
• Alternating red and green — Exercise extreme caution. This signal does not tell you to do a specific thing. It is a warning that conditions at the airport require your heightened attention. Treat it seriously and be prepared for anything.

A clean way to organize these in your memory is to group them by color family. Green signals are permissive — they are telling you something is allowed or to come back. Red signals are restrictive or cautionary — they are telling you to hold off or stay alert. Flashing white stands alone as a ground-only signal with no airborne meaning, and alternating red and green is the catch-all caution flag.

How to Acknowledge a Light Gun Signal

Receiving the signal is only half of the exchange. The tower controller needs to know you saw it, and you are required to acknowledge. The method depends on the time of day. During daylight hours, you acknowledge by rocking your wings. At night, you blink your landing light. Either action tells the controller that the message was received and understood. Failing to acknowledge is not just a procedural gap — it leaves the controller uncertain whether to send the signal again, issue a new one, or assume something has gone wrong. On your checkride, forgetting to mention acknowledgment is one of the most common ways candidates lose points on this question even after correctly listing all six signals.

What Happens After You Land Without a Radio

Suppose you do fly a lost-comm approach, receive the steady green after rocking your wings, land, and taxi clear. You are not done. Once you have parked and secured the aircraft, you are required to contact the tower by telephone as soon as practicable to advise them of the situation. This post-landing procedure is spelled out in the AIM and is a detail many candidates overlook entirely. The phone call closes the loop for the controller, confirms that the no-radio operation went as intended, and provides information that may be useful if any questions arise later about the sequence of events. Your examiner may very well ask what you do after you taxi to the ramp, so do not let that final step slip through.

Light gun signals are one of those topics that reward the pilot who takes the time to learn every detail rather than the broad strokes. Know all six, know the difference between flashing green and flashing white, acknowledge every signal you receive, and make that phone call after landing. If you want to practice questions like this in a realistic oral exam format, try SimulatedCheckride.com.