Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

8991AB

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-18359 · AIRBUS A-330-300

Hex
8991AB
Octal
42310653
Decimal
9,015,723
Country
TW
Tail
B-18359
Type
A333
No current signal · last broadcast 54m ago
Flights observed
189
Distinct callsigns
20
Country
TW
Last broadcast
54m ago

Last known position

Most recent position reported by Mode-S 8991AB.

Country allocation

The ICAO 24-bit address 8991AB falls within the block assigned to Taiwan (TW) by ICAO Annex 10, Volume III. Every aircraft registered in Taiwan receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 20 distinct

Callsign Airline Flights Last seen
CAL221 China Airlines 18 2026-05-30
CAL223 China Airlines 15 2026-05-29
CAL220 China Airlines 13 2026-05-30
CAL222 China Airlines 10 2026-05-28
CAL111 China Airlines 10 2026-05-07
CAL173 China Airlines 9 2026-05-07
CAL834 China Airlines 8 2026-05-12
CAL919 China Airlines 6 2026-05-12
CAL201 China Airlines 6 2026-05-27
CAL172 China Airlines 6 2026-05-07
CAL110 China Airlines 6 2026-05-06
CAL833 China Airlines 5 2026-05-07
CAL703 China Airlines 5 2026-05-05
CAL702 China Airlines 5 2026-05-09
CAL701 China Airlines 5 2026-05-09
CAL153 China Airlines 5 2026-05-01
CAL131 China Airlines 5 2026-04-30
CAL105 China Airlines 5 2026-05-02
CAL704 China Airlines 4 2026-05-05
CAL130 China Airlines 4 2026-04-30

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 CAL221 HND → TSA May 30, 08:25 UTCMay 30, 08:45 UTC20m
2026-05-30 CAL221 HND → TSA May 30, 05:45 UTCMay 30, 07:00 UTC1h 15m
2026-05-30 CAL220 TSA → HND May 30, 02:40 UTCMay 30, 03:50 UTC1h 10m
2026-05-30 CAL220 TSA → HND May 30, 01:10 UTCMay 30, 01:25 UTC15m
2026-05-29 CAL223 HND → TSA May 29, 01:35 UTCMay 29, 02:20 UTC45m
2026-05-28 CAL223 HND → TSA May 28, 23:10 UTCMay 29, 00:15 UTC1h 5m
2026-05-28 CAL222 TSA → HND May 28, 10:25 UTCMay 28, 13:40 UTC3h 15m
2026-05-28 CAL221 HND → TSA May 28, 08:30 UTCMay 28, 08:40 UTC10m
2026-05-28 CAL221 HND → TSA May 28, 05:50 UTCMay 28, 06:55 UTC1h 5m
2026-05-28 CAL220 TSA → HND May 28, 01:05 UTCMay 28, 03:50 UTC2h 45m
2026-05-27 CAL201 TSA → SHA May 27, 04:49 UTCMay 27, 09:50 UTC5h 0m
2026-05-26 CAL223 HND → TSA May 26, 23:10 UTCMay 27, 00:19 UTC1h 10m
2026-05-26 CAL222 TSA → HND May 26, 10:14 UTCMay 26, 13:04 UTC2h 50m
2026-05-26 CAL221 HND → TSA May 26, 08:19 UTCMay 26, 08:34 UTC15m
2026-05-26 CAL221 HND → TSA May 26, 05:45 UTCMay 26, 06:49 UTC1h 5m
2026-05-26 CAL220 TSA → HND May 26, 01:00 UTCMay 26, 03:45 UTC2h 45m
2026-05-25 CAL201 TSA → SHA May 25, 04:30 UTCMay 25, 09:55 UTC5h 25m
2026-05-25 CAL223 HND → TSA May 25, 01:55 UTCMay 25, 02:15 UTC20m
2026-05-24 CAL223 HND → TSA May 24, 23:15 UTCMay 24, 23:46 UTC31m
2026-05-24 CAL222 TSA → HND May 24, 10:35 UTCMay 24, 13:15 UTC2h 40m
2026-05-24 CAL221 HND → TSA May 24, 08:55 UTCMay 24, 09:05 UTC10m
2026-05-24 CAL221 HND → TSA May 24, 06:10 UTCMay 24, 07:20 UTC1h 10m
2026-05-24 CAL220 TSA → HND May 24, 01:05 UTCMay 24, 03:50 UTC2h 45m
2026-05-23 CAL201 TSA → SHA May 23, 04:45 UTCMay 23, 09:55 UTC5h 10m
2026-05-23 CAL223 HND → TSA May 23, 01:50 UTCMay 23, 02:25 UTC35m
2026-05-22 CAL223 HND → TSA May 22, 23:10 UTCMay 23, 00:20 UTC1h 10m
2026-05-22 CAL222 TSA → HND May 22, 11:05 UTCMay 22, 13:35 UTC2h 30m
2026-05-22 CAL221 HND → TSA May 22, 09:15 UTCMay 22, 09:30 UTC15m
2026-05-22 CAL221 HND → TSA May 22, 06:30 UTCMay 22, 07:15 UTC45m
2026-05-22 CAL220 TSA → HND May 22, 02:35 UTCMay 22, 03:45 UTC1h 10m
2026-05-22 CAL220 TSA → HND May 22, 01:05 UTCMay 22, 01:20 UTC15m
2026-05-21 CAL202 SHA → TSA May 21, 09:45 UTCMay 21, 10:00 UTC15m
2026-05-21 CAL201 TSA → SHA May 21, 04:35 UTCMay 21, 05:05 UTC30m
2026-05-21 CAL223 HND → TSA May 21, 01:35 UTCMay 21, 02:25 UTC50m
2026-05-20 CAL223 HND → TSA May 20, 22:55 UTCMay 21, 01:00 UTC2h 5m
2026-05-20 CAL222 TSA → HND May 20, 11:35 UTCMay 20, 12:55 UTC1h 20m
2026-05-20 CAL222 TSA → HND May 20, 10:05 UTCMay 20, 10:20 UTC15m
2026-05-20 CAL221 HND → TSA May 20, 08:15 UTCMay 20, 08:35 UTC20m
2026-05-20 CAL221 HND → TSA May 20, 05:35 UTCMay 20, 07:40 UTC2h 5m
2026-05-20 CAL220 TSA → HND May 20, 01:00 UTCMay 20, 03:50 UTC2h 50m
2026-05-19 CAL201 TSA → SHA May 19, 04:30 UTCMay 19, 10:20 UTC5h 50m
2026-05-19 CAL223 HND → TSA May 19, 01:30 UTCMay 19, 02:20 UTC50m
2026-05-18 CAL223 HND → TSA May 18, 23:05 UTCMay 19, 00:05 UTC1h 0m
2026-05-18 CAL222 TSA → HND May 18, 10:15 UTCMay 18, 13:10 UTC2h 55m
2026-05-18 CAL221 HND → TSA May 18, 08:05 UTCMay 18, 08:35 UTC30m
2026-05-18 CAL221 HND → TSA May 18, 05:45 UTCMay 18, 06:50 UTC1h 5m
2026-05-18 CAL220 TSA → HND May 18, 02:50 UTCMay 18, 04:11 UTC1h 20m
2026-05-18 CAL220 TSA → HND May 18, 01:10 UTCMay 18, 01:25 UTC15m
2026-05-17 CAL201 TSA → SHA May 17, 04:55 UTCMay 17, 10:00 UTC5h 5m
2026-05-17 CAL223 HND → TSA May 17, 01:30 UTCMay 17, 01:45 UTC15m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the B-18359 page for operator, model, and routing details .

Mode-S 8991AB frequently asked

What is Mode-S code 8991AB?
8991AB is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-18359.
Where is Mode-S 8991AB registered?
Mode-S code 8991AB is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8991AB broadcasting right now?
No active broadcast right now. Last signal was 54m ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8991AB, octal 42310653, decimal 9,015,723.
What flights does 8991AB operate?
Mode-S 8991AB has broadcast 20 distinct callsigns, including CAL221, CAL223, CAL220, CAL222, CAL111.