Where the data comes from, how accurate it is, and its limits

How one transmission flows

Receive: our own receiver stations pick up public civil aviation frequencies. Today there is one station, on Taoyuan Tower 118.7.
Store: each call is uploaded when it ends; audio goes to cloud storage (Cloudflare R2), the record to the database (Cloudflare D1), and live listeners get it immediately.
Transcribe: Google Gemini produces the English transcript and separates controller from pilot, guided by callsigns from the current schedule (MOTC TDX).
Check and translate: a Traditional Chinese translation and clearance tags are added, and numbers are checked against real runway, taxiway and frequency data; anything implausible is marked unclear.
Publish: the live view, search, timeline and flight pages update together.

Accuracy and speed (with dates and samples)

77% of subtitles usable as-is: 40 judged clips from the morning of 27 Sep 2026, 95% CI 65–88%. The judge shares a model family with the transcriber, so this is an optimistic estimate, measured before fixes P1–P8.
About 9 in 10 callsigns correct: 35/39 in the same audit.
Speed: end of call to subtitle written, median 6.8 s, p90 13.5 s (231 clips, excluding clips interrupted by deploys, 27 Sep 2026).
We do not quote a word error rate (WER) on the site; results from the retired pipeline do not describe today’s service.

What the automatic flags mean

Go-around?, rejected takeoff: detected automatically from the radio, not reviewed by a person.
Readback check (experimental): compares values between instruction and readback; unvalidated, offered only as a search filter and never shown on the public board.
Board statuses describe processing only (processing, transcribed, reviewed); they are not flight status.

Privacy rule

All emergency transmissions are hidden from public pages. A clip is hidden if it is flagged as an emergency, its event type contains EMERGENCY, its squawk is 7500/7600/7700, or the English transcript contains words such as mayday, pan pan, emergency, medevac or bird strike. We would rather hide by mistake than publish by mistake. We do not identify individual controllers or pilots, and never quote private community chat.

Frequencies and data sources

Civil aviation frequencies only; never military or joint-use airfields.
Schedules and METAR: MOTC TDX platform.
Aircraft positions: community ADS-B (adsb.lol, adsb.fi, ODbL); currently down, fix in progress.
Runways and frequencies: the AIP (Taiwan CAA aeronautical information).
The live service uses no LiveATC or other third-party audio.

What it must not be used for

For research, education and enthusiasts only. Never use it for air traffic control, flight planning or any operational decision. It is not an official record; the cause of any occurrence is for the Taiwan Transportation Safety Board to determine.

Corrections

Email hi@hungatc.com and we will fix it and note the change.