Does it need an internet connection?

Yes — it reads a live source, so it needs a connection to update.

Yes — free, no download, in your browser.

Does 7700 mean a crash is happening?

No. It declares a general emergency, which can include situations that end safely.

Why is the board usually empty?

The reserved emergency codes are rarely selected, so most of the time no aircraft in coverage is using one.

Emergency Squawk Watch Screensaver

The Emergency Squawk Watch screensaver shows aircraft currently transmitting an emergency transponder code — 7700 emergency, 7600 lost radio, 7500 interference — from the open ADS-B network. An empty board is the normal, good state. It's free, runs in your browser, and ESC exits.

How the Emergency Squawk Watch screensaver works

The background pipeline reads this from open ADS-B network and saves a snapshot the saver loads.

Aircraft currently transmitting an emergency transponder code — 7700 emergency, 7600 lost radio, 7500 interference — from the open ADS-B network.

It refreshes on a schedule, so what you see stays current.

Colours and the accent can be changed in settings; nothing is stored beyond your own browser.

What the emergency squawk codes mean

Aircraft carry a transponder that replies to radar with a four-digit code, called a squawk. Air traffic control assigns most codes, so controllers can tell aircraft apart on a screen. Each digit runs from 0 to 7, which gives 4,096 possible codes. Three are reserved worldwide: 7500 for unlawful interference such as a hijacking, 7600 for loss of radio communication and 7700 for a general emergency.

The data come from adsb.lol, a community-run flight-tracking project that describes its data as openly licensed. It collects ADS-B broadcasts, the position reports modern aircraft transmit, from receivers run by volunteers. The saver filters that stream for the three reserved codes and shows the aircraft details when they are available.

An empty board is normal, since these codes are rarely in use. A code on its own does not say what is happening on board: it can be set deliberately, by mistake, or left on after an event has been resolved. Coverage depends on where receivers are located, so aircraft far from any may not appear.

A worked example

Aircraft currently transmitting an emergency transponder code — 7700 emergency, 7600 lost radio, 7500 interference — from the open ADS-B network. An empty board is the normal, good state.

Settings & tips

Accent and Background recolour the display.
Run automation/run.py squawkwatch to refresh the feed.
Press ESC to leave fullscreen.

Frequently asked questions

Is this real data?: Yes — it comes from open ADS-B network and is refreshed on a schedule.
Is a key needed?: No. This source is fully key-less.
Does it need an internet connection?: Yes — it reads a live source, so it needs a connection to update.
Is it free?: Yes — free, no download, in your browser.
Does 7700 mean a crash is happening?: No. It declares a general emergency, which can include situations that end safely.
Why is the board usually empty?: The reserved emergency codes are rarely selected, so most of the time no aircraft in coverage is using one.

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