Apparatus

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sensors Mode-S transponder

8991A9

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-18361 · AIRBUS A-330-300

Hex
8991A9
Octal
42310651
Decimal
9,015,721
Country
TW
Tail
B-18361
Type
A333
No current signal · last broadcast 1h ago
Flights observed
198
Distinct callsigns
20
Country
TW
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S 8991A9.

Country allocation

The ICAO 24-bit address 8991A9 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 16 2026-05-12
CAL223 China Airlines 15 2026-05-13
CAL220 China Airlines 14 2026-05-12
CAL222 China Airlines 13 2026-05-12
CAL919 China Airlines 11 2026-05-25
CAL105 China Airlines 11 2026-05-23
CAL920 China Airlines 9 2026-05-25
CAL834 China Airlines 9 2026-05-29
CAL833 China Airlines 8 2026-05-28
CAL704 China Airlines 6 2026-05-26
CAL703 China Airlines 6 2026-05-26
CAL104 China Airlines 6 2026-05-23
CAL161 China Airlines 5 2026-05-28
CAL153 China Airlines 5 2026-05-27
CAL701 China Airlines 4 2026-04-17
CAL202 China Airlines 4 2026-05-13
CAL201 China Airlines 4 2026-05-11
CAL111 China Airlines 4 2026-05-26
CAL101 China Airlines 4 2026-04-29
CAL702 China Airlines 3 2026-04-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 CAL120 TPE → OKA May 30, 00:30 UTCMay 30, 00:50 UTC20m
2026-05-29 CAL834 BKK → TPE May 29, 04:15 UTCMay 29, 07:25 UTC3h 10m
2026-05-28 CAL833 TPE → BKK May 28, 23:20 UTCMay 29, 02:35 UTC3h 15m
2026-05-28 CAL163 ICN → TPE May 28, 12:15 UTCMay 28, 14:15 UTC2h 0m
2026-05-28 CAL162 TPE → ICN May 28, 08:05 UTCMay 28, 10:05 UTC2h 0m
2026-05-28 CAL161 ICN → TPE May 28, 04:25 UTCMay 28, 06:30 UTC2h 5m
2026-05-28 CAL160 TPE → ICN May 28, 00:30 UTCMay 28, 02:30 UTC2h 0m
2026-05-27 CAL153 KIX → TPE May 27, 07:40 UTCMay 27, 08:10 UTC30m
2026-05-27 CAL153 KIX → TPE May 27, 05:49 UTCMay 27, 06:25 UTC35m
2026-05-27 CAL152 TPE → KIX May 27, 01:34 UTCMay 27, 03:59 UTC2h 25m
2026-05-26 CAL704 MNL → TPE May 26, 09:09 UTCMay 26, 11:05 UTC1h 55m
2026-05-26 CAL703 TPE → MNL May 26, 05:49 UTCMay 26, 07:34 UTC1h 45m
2026-05-26 CAL111 FUK → TPE May 26, 04:00 UTCMay 26, 04:24 UTC25m
2026-05-26 CAL111 FUK → TPE May 26, 02:35 UTCMay 26, 02:44 UTC10m
2026-05-25 CAL110 TPE → FUK May 25, 23:04 UTCMay 25, 23:30 UTC25m
2026-05-25 CAL920 HKG → TPE May 25, 12:40 UTCMay 25, 14:00 UTC1h 20m
2026-05-25 CAL919 TPE → HKG May 25, 10:30 UTCMay 25, 10:50 UTC20m
2026-05-25 CAL919 TPE → HKG May 25, 09:30 UTCMay 25, 09:55 UTC25m
2026-05-25 CAL153 KIX → TPE May 25, 07:30 UTCMay 25, 08:00 UTC30m
2026-05-25 CAL153 KIX → TPE May 25, 05:35 UTCMay 25, 06:10 UTC35m
2026-05-25 CAL152 TPE → KIX May 25, 02:55 UTCMay 25, 03:45 UTC50m
2026-05-24 CAL920 HKG → TPE May 24, 12:45 UTCMay 24, 14:10 UTC1h 25m
2026-05-24 CAL919 TPE → HKG May 24, 10:55 UTCMay 24, 11:10 UTC15m
2026-05-24 CAL919 TPE → HKG May 24, 09:55 UTCMay 24, 10:20 UTC25m
2026-05-24 CAL834 BKK → TPE May 24, 04:35 UTCMay 24, 08:30 UTC3h 55m
2026-05-23 CAL833 TPE → BKK May 23, 23:20 UTCMay 24, 02:40 UTC3h 20m
2026-05-23 CAL105 NRT → TPE May 23, 12:30 UTCMay 23, 12:55 UTC25m
2026-05-23 CAL105 NRT → TPE May 23, 09:50 UTCMay 23, 11:10 UTC1h 20m
2026-05-23 CAL104 TPE → NRT May 23, 05:10 UTCMay 23, 07:50 UTC2h 40m
2026-05-22 CAL916 HKG → TPE May 22, 11:35 UTCMay 22, 11:55 UTC20m
2026-05-22 CAL916 HKG → TPE May 22, 10:45 UTCMay 22, 11:00 UTC15m
2026-05-22 CAL915 TPE → HKG May 22, 09:05 UTCMay 22, 09:20 UTC15m
2026-05-22 CAL915 TPE → HKG May 22, 08:00 UTCMay 22, 08:30 UTC30m
2026-05-22 CAL161 ICN → TPE May 22, 05:50 UTCMay 22, 06:10 UTC20m
2026-05-22 CAL161 ICN → TPE May 22, 04:05 UTCMay 22, 04:30 UTC25m
2026-05-22 CAL160 TPE → ICN May 22, 00:05 UTCMay 22, 02:15 UTC2h 10m
2026-05-21 CAL528 SZX → TPE May 21, 11:30 UTCMay 21, 12:05 UTC35m
2026-05-21 CAL528 SZX → TPE May 21, 10:40 UTCMay 21, 10:50 UTC10m
2026-05-21 CAL527 TPE → SZX May 21, 07:35 UTCMay 21, 08:05 UTC30m
2026-05-21 MDA991 TPE → TPE May 21, 01:30 UTCMay 21, 05:55 UTC4h 25m
2026-05-20 CAL105 NRT → TPE May 20, 12:10 UTCMay 20, 12:25 UTC15m
2026-05-20 CAL105 NRT → TPE May 20, 09:25 UTCMay 20, 10:35 UTC1h 10m
2026-05-20 CAL104 TPE → NRT May 20, 04:30 UTCMay 20, 07:25 UTC2h 56m
2026-05-19 CAL105 NRT → TPE May 19, 12:05 UTCMay 19, 12:20 UTC15m
2026-05-19 CAL105 NRT → TPE May 19, 09:35 UTCMay 19, 10:40 UTC1h 5m
2026-05-19 CAL104 TPE → NRT May 19, 04:40 UTCMay 19, 07:40 UTC3h 0m
2026-05-18 CAL153 KIX → TPE May 18, 05:15 UTCMay 18, 07:45 UTC2h 30m
2026-05-18 CAL152 TPE → KIX May 18, 01:10 UTCMay 18, 03:30 UTC2h 20m
2026-05-17 CAL836 BKK → TPE May 17, 11:35 UTCMay 17, 14:50 UTC3h 15m
2026-05-17 CAL835 TPE → BKK May 17, 06:20 UTCMay 17, 09:45 UTC3h 25m

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-18361 page for operator, model, and routing details .

Mode-S 8991A9 frequently asked

What is Mode-S code 8991A9?
8991A9 is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-18361.
Where is Mode-S 8991A9 registered?
Mode-S code 8991A9 is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8991A9 broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8991A9, octal 42310651, decimal 9,015,721.
What flights does 8991A9 operate?
Mode-S 8991A9 has broadcast 20 distinct callsigns, including CAL221, CAL223, CAL220, CAL222, CAL919.