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 Jul 26, 14:45 UTC
Flights observed
391
Distinct callsigns
20
Country
TW
Last broadcast
Jul 26, 14:45 UTC

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 - 40 2026-07-13
CAL223 - 39 2026-07-14
CAL222 - 30 2026-07-13
CAL220 - 30 2026-07-13
CAL105 - 15 2026-07-18
CAL834 China Airlines 13 2026-07-21
CAL833 - 13 2026-07-20
CAL201 - 13 2026-07-14
CAL919 China Airlines 11 2026-05-25
CAL153 - 11 2026-07-17
CAL111 China Airlines 11 2026-07-22
CAL920 China Airlines 9 2026-05-25
CAL703 China Airlines 9 2026-07-19
CAL701 China Airlines 9 2026-07-24
CAL110 - 9 2026-07-22
CAL104 China Airlines 9 2026-07-18
CAL704 China Airlines 8 2026-07-19
CAL702 China Airlines 8 2026-07-25
CAL202 - 8 2026-07-05
CAL161 China Airlines 8 2026-07-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 CAL836 BKK → TPE Jul 26, 11:10 UTCJul 26, 14:35 UTC3h 25m
2026-07-26 CAL835 TPE → BKK Jul 26, 05:50 UTCJul 26, 09:10 UTC3h 21m
2026-07-25 CAL522 CAN → TPE Jul 25, 12:20 UTCJul 25, 13:15 UTC55m
2026-07-25 CAL521 TPE → CAN Jul 25, 06:25 UTCJul 25, 07:55 UTC1h 30m
2026-07-25 CAL702 MNL → TPE Jul 25, 02:55 UTCJul 25, 04:45 UTC1h 50m
2026-07-24 CAL701 TPE → MNL Jul 24, 23:50 UTCJul 25, 01:30 UTC1h 40m
2026-07-24 CAL163 ICN → TPE Jul 24, 14:00 UTCJul 24, 14:45 UTC45m
2026-07-24 CAL163 ICN → TPE Jul 24, 12:00 UTCJul 24, 12:40 UTC40m
2026-07-24 CAL162 TPE → ICN Jul 24, 08:20 UTCJul 24, 10:20 UTC2h 0m
2026-07-24 CAL161 ICN → TPE Jul 24, 06:25 UTCJul 24, 06:50 UTC25m
2026-07-24 CAL161 ICN → TPE Jul 24, 04:45 UTCJul 24, 05:20 UTC35m
2026-07-24 CAL160 TPE → ICN Jul 24, 01:00 UTCJul 24, 03:00 UTC2h 0m
2026-07-23 CAL163 ICN → TPE Jul 23, 11:55 UTCJul 23, 14:05 UTC2h 10m
2026-07-23 CAL162 TPE → ICN Jul 23, 08:00 UTCJul 23, 10:05 UTC2h 5m
2026-07-23 CAL161 ICN → TPE Jul 23, 04:30 UTCJul 23, 06:30 UTC2h 0m
2026-07-23 CAL160 TPE → ICN Jul 23, 00:25 UTCJul 23, 02:35 UTC2h 10m
2026-07-22 CAL528 - Jul 22, 11:40 UTCJul 22, 12:55 UTC1h 15m
2026-07-22 CAL111 FUK → TPE Jul 22, 03:15 UTCJul 22, 04:20 UTC1h 5m
2026-07-22 CAL111 FUK → TPE Jul 22, 02:25 UTCJul 22, 02:40 UTC15m
2026-07-22 CAL110 - Jul 22, 00:25 UTCJul 22, 00:40 UTC15m
2026-07-21 CAL110 - Jul 21, 23:05 UTCJul 21, 23:30 UTC25m
2026-07-21 CAL834 BKK → TPE Jul 21, 04:05 UTCJul 21, 07:35 UTC3h 30m
2026-07-20 CAL833 TPE → BKK Jul 20, 23:15 UTCJul 21, 02:30 UTC3h 14m
2026-07-20 CAL528 - Jul 20, 10:15 UTCJul 20, 11:35 UTC1h 20m
2026-07-20 CAL527 TPE → SZX Jul 20, 07:05 UTCJul 20, 08:25 UTC1h 20m
2026-07-20 CAL702 MNL → TPE Jul 20, 02:45 UTCJul 20, 04:30 UTC1h 45m
2026-07-19 CAL701 TPE → MNL Jul 19, 23:40 UTCJul 20, 01:20 UTC1h 40m
2026-07-19 CAL704 MNL → TPE Jul 19, 09:20 UTCJul 19, 11:05 UTC1h 45m
2026-07-19 CAL703 TPE → MNL Jul 19, 05:55 UTCJul 19, 07:45 UTC1h 50m
2026-07-19 CAL111 - Jul 19, 04:10 UTCJul 19, 04:35 UTC25m
2026-07-19 CAL111 - Jul 19, 02:50 UTCJul 19, 03:10 UTC20m
2026-07-19 CAL110 - Jul 19, 00:45 UTCJul 19, 01:05 UTC20m
2026-07-18 CAL110 - Jul 18, 23:20 UTCJul 18, 23:50 UTC30m
2026-07-18 CAL105 - Jul 18, 12:05 UTCJul 18, 12:25 UTC20m
2026-07-18 CAL105 - Jul 18, 09:40 UTCJul 18, 10:55 UTC1h 15m
2026-07-18 CAL104 TPE → NRT Jul 18, 06:40 UTCJul 18, 07:40 UTC1h 0m
2026-07-18 CAL104 TPE → NRT Jul 18, 04:40 UTCJul 18, 04:55 UTC15m
2026-07-17 CAL153 - Jul 17, 07:20 UTCJul 17, 07:50 UTC30m
2026-07-17 CAL153 - Jul 17, 05:35 UTCJul 17, 06:15 UTC40m
2026-07-17 CAL152 TPE → KIX Jul 17, 01:45 UTCJul 17, 04:04 UTC2h 20m
2026-07-15 CAL834 - Jul 15, 04:10 UTCJul 15, 07:35 UTC3h 25m
2026-07-15 CAL833 - Jul 15, 02:15 UTCJul 15, 02:30 UTC15m
2026-07-14 CAL833 - Jul 14, 23:30 UTCJul 15, 00:30 UTC1h 0m
2026-07-14 CAL7846 TSA → TPE Jul 14, 12:25 UTCJul 14, 12:40 UTC15m
2026-07-14 CAL201 TSA → TSA Jul 14, 04:50 UTCJul 14, 10:00 UTC5h 10m
2026-07-14 CAL223 - Jul 14, 01:35 UTCJul 14, 01:55 UTC20m
2026-07-13 CAL223 - Jul 13, 23:10 UTCJul 14, 00:20 UTC1h 10m
2026-07-13 CAL222 TSA → HND Jul 13, 10:15 UTCJul 13, 13:00 UTC2h 45m
2026-07-13 CAL221 - Jul 13, 08:20 UTCJul 13, 08:40 UTC20m
2026-07-13 CAL221 - Jul 13, 05:50 UTCJul 13, 07:01 UTC1h 10m

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 Jul 26, 14:45 UTC.
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, CAL222, CAL220, CAL105.