sensors Mode-S transponder

8991B9

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-18311 · AIRBUS A-330-300

Hex
8991B9
Octal
42310671
Decimal
9,015,737
Country
TW
Tail
B-18311
Type
A333
No current signal · last broadcast 12h ago
Flights observed
178
Distinct callsigns
20
Country
TW
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S 8991B9.

Country allocation

The ICAO 24-bit address 8991B9 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
CAL173 China Airlines 14 2026-05-28
CAL105 China Airlines 13 2026-05-29
CAL104 China Airlines 11 2026-05-29
CAL172 China Airlines 10 2026-05-28
CAL702 China Airlines 9 2026-05-24
CAL701 China Airlines 8 2026-05-23
CAL704 China Airlines 7 2026-05-21
CAL703 China Airlines 7 2026-05-21
CAL601 China Airlines 6 2026-05-21
CAL521 China Airlines 5 2026-05-07
CAL110 China Airlines 5 2026-05-22
CAL834 China Airlines 4 2026-05-09
CAL791 China Airlines 4 2026-05-23
CAL602 China Airlines 4 2026-05-21
CAL163 China Airlines 4 2026-05-22
CAL162 China Airlines 4 2026-05-22
CAL161 China Airlines 4 2026-05-16
CAL160 China Airlines 4 2026-05-16
CAL117 China Airlines 4 2026-05-06
CAL111 China Airlines 4 2026-05-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 CAL105 NRT → TPE May 29, 13:20 UTCMay 29, 16:30 UTC3h 10m
2026-05-29 CAL104 TPE → NRT May 29, 04:45 UTCMay 29, 07:35 UTC2h 50m
2026-05-28 CAL173 KIX → TPE May 28, 12:45 UTCMay 28, 13:05 UTC20m
2026-05-28 CAL173 KIX → TPE May 28, 10:50 UTCMay 28, 11:30 UTC40m
2026-05-28 CAL172 TPE → KIX May 28, 07:00 UTCMay 28, 09:25 UTC2h 25m
2026-05-27 CAL105 NRT → TPE May 27, 12:25 UTCMay 27, 12:50 UTC25m
2026-05-27 CAL105 NRT → TPE May 27, 09:50 UTCMay 27, 11:05 UTC1h 15m
2026-05-27 CAL104 TPE → NRT May 27, 04:34 UTCMay 27, 07:35 UTC3h 0m
2026-05-26 CAL105 NRT → TPE May 26, 12:00 UTCMay 26, 12:20 UTC20m
2026-05-26 CAL105 NRT → TPE May 26, 09:25 UTCMay 26, 10:44 UTC1h 20m
2026-05-26 CAL104 TPE → NRT May 26, 04:24 UTCMay 26, 07:19 UTC2h 55m
2026-05-25 CAL792 HAN → TPE May 25, 06:25 UTCMay 25, 07:55 UTC1h 30m
2026-05-24 CAL173 KIX → TPE May 24, 10:30 UTCMay 24, 13:00 UTC2h 30m
2026-05-24 CAL172 TPE → KIX May 24, 06:40 UTCMay 24, 09:00 UTC2h 20m
2026-05-24 CAL702 MNL → TPE May 24, 02:40 UTCMay 24, 04:40 UTC2h 0m
2026-05-23 CAL701 TPE → MNL May 23, 23:30 UTCMay 24, 01:20 UTC1h 50m
2026-05-23 CAL924 HKG → TPE May 23, 13:40 UTCMay 23, 14:55 UTC1h 15m
2026-05-23 CAL923 TPE → HKG May 23, 10:30 UTCMay 23, 11:45 UTC1h 15m
2026-05-23 CAL791 TPE → HAN May 23, 00:45 UTCMay 23, 07:00 UTC6h 14m
2026-05-22 CAL163 ICN → TPE May 22, 11:50 UTCMay 22, 14:15 UTC2h 25m
2026-05-22 CAL162 TPE → ICN May 22, 08:20 UTCMay 22, 10:25 UTC2h 5m
2026-05-22 CAL111 FUK → TPE May 22, 06:15 UTCMay 22, 06:30 UTC15m
2026-05-22 CAL110 TPE → FUK May 22, 01:00 UTCMay 22, 01:10 UTC10m
2026-05-21 CAL110 TPE → FUK May 21, 23:10 UTCMay 21, 23:35 UTC25m
2026-05-21 CAL704 MNL → TPE May 21, 09:40 UTCMay 21, 11:30 UTC1h 50m
2026-05-21 CAL703 TPE → MNL May 21, 06:25 UTCMay 21, 08:10 UTC1h 45m
2026-05-21 CAL602 HKG → TPE May 21, 04:25 UTCMay 21, 05:00 UTC35m
2026-05-21 CAL602 HKG → TPE May 21, 03:35 UTCMay 21, 03:50 UTC15m
2026-05-21 CAL601 TPE → HKG May 21, 01:35 UTCMay 21, 01:50 UTC15m
2026-05-21 CAL601 TPE → HKG May 21, 00:30 UTCMay 21, 01:00 UTC30m
2026-05-20 CAL173 KIX → TPE May 20, 12:40 UTCMay 20, 13:00 UTC20m
2026-05-20 CAL173 KIX → TPE May 20, 10:40 UTCMay 20, 12:10 UTC1h 30m
2026-05-20 CAL172 TPE → KIX May 20, 06:40 UTCMay 20, 09:10 UTC2h 30m
2026-05-20 CAL702 MNL → TPE May 20, 03:00 UTCMay 20, 04:45 UTC1h 46m
2026-05-19 CAL701 TPE → MNL May 19, 23:40 UTCMay 20, 01:30 UTC1h 50m
2026-05-19 CAL173 KIX → TPE May 19, 12:30 UTCMay 19, 12:50 UTC20m
2026-05-19 CAL173 KIX → TPE May 19, 10:35 UTCMay 19, 11:10 UTC35m
2026-05-19 CAL172 TPE → KIX May 19, 06:25 UTCMay 19, 08:45 UTC2h 20m
2026-05-19 CAL702 MNL → TPE May 19, 02:55 UTCMay 19, 04:45 UTC1h 50m
2026-05-18 CAL701 TPE → MNL May 18, 23:50 UTCMay 19, 01:35 UTC1h 45m
2026-05-18 CAL105 NRT → TPE May 18, 09:15 UTCMay 18, 12:05 UTC2h 50m
2026-05-18 CAL104 TPE → NRT May 18, 05:10 UTCMay 18, 07:35 UTC2h 25m
2026-05-18 CAL104 TPE → NRT May 18, 04:25 UTCMay 18, 04:40 UTC15m
2026-05-17 CAL173 KIX → TPE May 17, 12:35 UTCMay 17, 13:05 UTC30m
2026-05-17 CAL173 KIX → TPE May 17, 10:35 UTCMay 17, 12:05 UTC1h 30m
2026-05-17 CAL172 TPE → KIX May 17, 06:40 UTCMay 17, 09:00 UTC2h 20m
2026-05-17 CAL702 MNL → TPE May 17, 02:55 UTCMay 17, 04:30 UTC1h 35m
2026-05-16 CAL701 TPE → MNL May 16, 23:45 UTCMay 17, 01:25 UTC1h 40m
2026-05-16 CAL161 ICN → TPE May 16, 04:15 UTCMay 16, 06:25 UTC2h 11m
2026-05-16 CAL160 TPE → ICN May 16, 00:35 UTCMay 16, 02:40 UTC2h 5m

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-18311 page for operator, model, and routing details .

Mode-S 8991B9 frequently asked

What is Mode-S code 8991B9?
8991B9 is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-18311.
Where is Mode-S 8991B9 registered?
Mode-S code 8991B9 is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8991B9 broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8991B9, octal 42310671, decimal 9,015,737.
What flights does 8991B9 operate?
Mode-S 8991B9 has broadcast 20 distinct callsigns, including CAL173, CAL105, CAL104, CAL172, CAL702.