Flight Operations

Squawk Codes Explained: 1200, 7500, 7600, 7700 and What They Mean to a Drone Pilot

A squawk code is the four-digit number a transponder replies with. Here is the full US list, what each emergency code triggers on a controller's screen, and why your drone is legally forbidden from squawking at all.

Jordan Reed·September 22, 2026·9 min read

Key takeaway

A Part 107 drone may not operate a transponder at all, so you will never squawk a code. The codes still matter, because 7600 tells you an aircraft near your site has no radio and cannot hear anyone.

A squawk code is the four-digit octal number an aircraft's transponder replies with so ATC radar can tag it. 1200 is the standard US VFR code. 7500 means hijacking, 7600 means lost radio, and 7700 means a general emergency. A Part 107 drone squawks none of them, because it is forbidden to carry an operating transponder.

That last point is where drone pilots usually stop reading, and it is the wrong place to stop. You will never dial a squawk code. You will, however, open a tracking app before a job and see a four-digit number next to every aircraft within ten miles of your launch point, and one of those numbers tells you that the pilot cannot hear a radio call from anybody.

What is a squawk code, and why is it called that?

A transponder is a radio that answers questions. Ground radar sends an interrogation, the transponder replies with a code and, if it has Mode C, with the aircraft's pressure altitude in 100-foot increments. The controller's screen stops showing an anonymous blip and starts showing a tagged target with a callsign and an altitude.

The word "squawk" is inherited from World War II. The British IFF system that identified friendly aircraft was code-named Parrot, so telling a crew to switch it on became "squawk your parrot." The equipment changed completely. The verb never did.

The code itself is four octal digits, which means each digit runs 0 through 7. That gives 4,096 possible codes, and the FAA allocates them nationally through Order JO 7110.66H, the National Beacon Code Allocation Plan. Most are assigned to a facility and handed out one flight at a time. A handful mean the same thing everywhere in the country, and those are the ones worth memorizing.

The squawk codes list

These are the fixed-meaning codes in US airspace. Everything not on this list is a discrete code assigned by a controller to one aircraft for one flight.

Code	Meaning	Who uses it
1200	VFR, not receiving radar services	Any VFR aircraft, at any altitude
1201	VFR in the Los Angeles Special Flight Rules Area	Aircraft in the LA SFRA corridor
1202	VFR glider not in contact with ATC	Gliders, in lieu of 1200
1255	Firefighting aircraft not in contact with ATC	Air tankers and lead planes on a fire
1277	Search and rescue aircraft	Civil aircraft on an authorized USAF or USCG SAR mission
7400	Unmanned aircraft, lost link	Transponder-equipped UAS on a COA
7500	Hijacking or other unlawful interference	Any aircraft
7600	Two-way radio communications failure	Any aircraft
7700	General emergency	Any aircraft
7777	Military interceptor operations	Never a civil aircraft

The three 7x00 emergency codes are why the octal system matters. They sit at the top of the range, they are far apart from the routine 1200 block, and they are hard to select by accident in one turn of a knob. That spacing was deliberate.

What do 7500, 7600 and 7700 actually mean?

Each one triggers something different at the facility, and the difference is worth understanding rather than just memorizing.

7700 is the general emergency code. The AIM instructs a pilot in distress to squawk Mode 3/A Code 7700 with Mode C altitude reporting, then immediately establish communications with ATC. Radar facilities are configured so that Code 7700 normally triggers an alarm or special indicator at all control positions, not just the one working that sector. Engine failure, fire, medical emergency, fuel exhaustion — one code covers all of it. The AIM also notes the honest limitation: a pilot might not be in radar coverage at all, so they should keep squawking 7700 and keep trying the radio.

7600 means the radio has failed. It is the one code that communicates by existing, because the aircraft transmitting it cannot tell anybody anything else. The controller sees 7600, stops expecting replies, clears a path, and anticipates that the pilot will fly the standard lost-communications procedure. Nothing about the aircraft is broken except its ability to talk.

7500 means unlawful interference. The AIM is blunt that Code 7500 will never be assigned by ATC without prior notification from the pilot that the aircraft is being subjected to unlawful interference, and that it triggers the special emergency indicator at all radar facilities. A controller who sees it asks the pilot to verify. If the pilot confirms, or says nothing, the controller stops asking questions and notifies the authorities. If it was a fat-finger error, the pilot says so and is asked to correct the setting. There is no version of this that goes unnoticed.

What is code 1200, the VFR squawk code?

It is the default. AIM 4-1-20 puts it plainly: unless otherwise instructed by an ATC facility, adjust the transponder to reply on Mode 3/A Code 1200 regardless of altitude.

Two details catch people out. First, "regardless of altitude" is literal — there is no separate high-altitude VFR code in the US, unlike the ICAO 7000 used across much of the rest of the world. Second, 1200 is not an off switch. A 1200 target still paints on radar with a Mode C altitude, which is exactly what lets a controller working IFR traffic see the VFR aircraft nobody is talking to and route around it.

Under 14 CFR 91.215(c), a pilot of an aircraft with an operable transponder must operate it and reply on the appropriate code or as assigned by ATC. The transponder is not optional equipment you may switch off because you would rather not be seen.

The codes you must never dial through

There is a procedural trap inside the four-digit knob, and the AIM spells it out. When you change codes, you can sweep through an emergency code on the way. Switching from 2700 to 7200 by turning the first digit from 2 to 7 while the rest still reads 700 puts 7700 on the air, and at that instant every controller within range gets an alarm.

The AIM's fix is to change the harmless digit first: go 2700 to 2200, then 2200 to 7200 — never through 7700. The same logic applies to 7500 and 7600.

Code 7777 is a harder line. The AIM states that under no circumstances should the pilot of a civil aircraft operate the transponder on Code 7777, which is reserved for military interceptor operations. It is not a secret alert. It is somebody else's code, and squawking it tells the system a fighter is running an intercept.

Does a Part 107 drone squawk anything?

No, and this is the part most squawk-code guides get wrong for a drone audience, because they are written for manned pilots.

14 CFR 107.52 states that unless otherwise authorized by the Administrator, no person may operate a small unmanned aircraft system under Part 107 with a transponder on. 14 CFR 107.53 does the same for ADS-B Out in transmit mode. Both arrived with the 2021 rulemaking that produced Remote ID, and the reasoning is spectrum capacity: there are vastly more drones than airplanes, and if every one of them started replying to radar interrogations the targets controllers actually need would disappear into the noise. Remote ID handles drone identification without touching the surveillance frequencies.

So the transponder requirement inside the Mode C veil asks for equipment your aircraft is banned from operating. The requirement never reaches you.

Code 7400 is the one exception worth knowing, and it is not yours. AIM Chapter 11 covers unmanned aircraft operating under a Certificate of Waiver or Authorization — the large, transponder-equipped platforms, not a Part 107 quadcopter. Transponder-equipped UAS experiencing a lost link squawk 7400 if capable, and 7600 if the aircraft is not programmed for 7400. The aircraft then flies a pre-programmed lost-link profile filed in its COA. Your own lost link procedure is a return-to-home setting and a phone call, not a code.

What this means when you are actually working

You are not transmitting, so the practical value of all this is in reading, not squawking.

Open any ADS-B tracking app at a job site and the squawk field is there next to each target. A screen full of 1200s tells you the traffic overhead is VFR and not talking to anybody, which is the most likely kind of aircraft to descend into your working altitude without warning. A discrete code like 4271 tells you that aircraft is on an ATC frequency being watched by a controller, which is marginally more predictable.

A 7600 near your site is the one that should change your plan. It means an aircraft is in the area with no radio. It cannot hear a Unicom call, it cannot be given instructions, and at a towered field it is being handled by light gun signals instead. Its flight path is whatever the standard lost-comms procedure says it should be, which near an airport means joining a published pattern you may or may not have anticipated.

A 7700 means an aircraft has a live emergency and may be maneuvering for any available surface. Neither one gives you a regulatory obligation — 107.37 already requires you to yield the right of way to every manned aircraft, without exception and regardless of what it is squawking. What they give you is warning. Land, and wait it out.

One caveat on the tracking apps: they show you what is transmitting ADS-B Out. An aircraft without it is invisible to the app and entirely visible to your eyes. The app supplements your scan. It never replaces it.

Frequently asked questions

What does squawk 7777 mean?

Code 7777 is reserved for military interceptor operations. The AIM states that under no circumstances should the pilot of a civil aircraft operate the transponder on this code. It is not an emergency signal or a covert alert, and squawking it indicates to the air defense system that a military intercept is in progress.

What does squawking 7700 mean?

7700 is the general aviation emergency code, covering any distress situation from engine failure to a medical emergency on board. It triggers an alarm or special indicator at every control position in the radar facility, not only the sector working the flight. A pilot squawks 7700 and then establishes radio contact with ATC as soon as possible.

What is a 7500 squawk?

7500 signals hijacking or other unlawful interference with the flight. It sets off the special emergency indicator at all radar ATC facilities, and a controller will ask the pilot to verify the code. ATC never assigns 7500 without the pilot first reporting unlawful interference, so seeing it on a screen is always pilot-initiated.

What does squawk 7400 mean?

7400 indicates an unmanned aircraft that has lost its command and control link. It applies to transponder-equipped UAS operating under a Certificate of Waiver or Authorization, which then fly a pre-programmed lost-link profile. A Part 107 drone never uses it, because 14 CFR 107.52 prohibits operating a transponder under Part 107 at all.

What squawk code do drones use?

Under Part 107, none. Sections 107.52 and 107.53 prohibit operating a small UAS with a transponder on or with ADS-B Out in transmit mode unless the Administrator authorizes it. Drone identification is handled by Remote ID broadcast instead, which uses Bluetooth or Wi-Fi rather than the aviation surveillance frequencies.

Is 1200 the same as squawking VFR?

Yes. In the United States, 1200 is the code for VFR flight when not receiving radar services, at any altitude. The ICAO equivalent used in much of the rest of the world is 7000, which is why non-US sources list a different number. Gliders squawk 1202 instead, and firefighting aircraft 1255.

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Editorial note: FAA rules and guidance may change. Confirm current operational requirements with official FAA resources before every flight. Updated September 22, 2026.