Apparatus

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sensors Mode-S transponder

8991AA

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-18358 · AIRBUS A-330-300

Hex
8991AA
Octal
42310652
Decimal
9,015,722
Country
TW
Tail
B-18358
Type
A333
No current signal · last broadcast Jul 26, 09:50 UTC
Flights observed
424
Distinct callsigns
20
Country
TW
Last broadcast
Jul 26, 09:50 UTC

Last known position

Most recent position reported by Mode-S 8991AA.

Country allocation

The ICAO 24-bit address 8991AA 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
CAL223 China Airlines 52 2026-07-26
CAL221 China Airlines 45 2026-07-25
CAL222 China Airlines 43 2026-07-25
CAL220 China Airlines 38 2026-07-25
CAL201 China Airlines 21 2026-07-26
CAL202 - 16 2026-07-20
CAL173 - 14 2026-07-02
CAL105 - 14 2026-07-06
CAL704 - 12 2026-07-03
CAL703 - 12 2026-07-03
CAL104 - 12 2026-07-06
CAL111 - 11 2026-06-30
CAL172 - 10 2026-07-02
CAL919 - 8 2026-06-29
CAL701 China Airlines 8 2026-07-03
CAL153 China Airlines 8 2026-05-13
CAL110 China Airlines 8 2026-06-29
CAL702 - 7 2026-07-04
CAL131 - 7 2026-07-13
CAL130 - 7 2026-07-13

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 CAL201 TSA → SHA Jul 26, 04:30 UTCJul 26, 09:45 UTC5h 16m
2026-07-26 CAL223 HND → TSA Jul 26, 01:45 UTCJul 26, 02:20 UTC35m
2026-07-25 CAL223 HND → TSA Jul 25, 23:20 UTCJul 26, 00:25 UTC1h 5m
2026-07-25 CAL222 TSA → HND Jul 25, 11:55 UTCJul 25, 13:00 UTC1h 5m
2026-07-25 CAL222 TSA → HND Jul 25, 10:20 UTCJul 25, 10:25 UTC5m
2026-07-25 CAL221 HND → TSA Jul 25, 08:20 UTCJul 25, 08:35 UTC15m
2026-07-25 CAL221 HND → TSA Jul 25, 05:40 UTCJul 25, 06:45 UTC1h 5m
2026-07-25 CAL220 TSA → HND Jul 25, 02:40 UTCJul 25, 04:05 UTC1h 25m
2026-07-25 CAL220 TSA → HND Jul 25, 01:10 UTCJul 25, 01:15 UTC5m
2026-07-24 CAL223 HND → TSA Jul 24, 01:35 UTCJul 24, 01:55 UTC20m
2026-07-23 CAL223 HND → TSA Jul 23, 23:05 UTCJul 24, 00:05 UTC1h 0m
2026-07-23 CAL222 TSA → HND Jul 23, 11:50 UTCJul 23, 13:05 UTC1h 15m
2026-07-23 CAL222 TSA → HND Jul 23, 10:15 UTCJul 23, 10:25 UTC10m
2026-07-23 CAL221 HND → TSA Jul 23, 08:15 UTCJul 23, 08:30 UTC15m
2026-07-23 CAL221 HND → TSA Jul 23, 05:40 UTCJul 23, 06:40 UTC1h 0m
2026-07-23 CAL220 TSA → HND Jul 23, 02:45 UTCJul 23, 04:00 UTC1h 15m
2026-07-23 CAL220 TSA → HND Jul 23, 01:10 UTCJul 23, 01:15 UTC5m
2026-07-22 CAL201 TSA → SHA Jul 22, 04:40 UTCJul 22, 05:15 UTC35m
2026-07-22 CAL223 - Jul 22, 01:55 UTCJul 22, 02:00 UTC5m
2026-07-21 CAL223 - Jul 21, 23:15 UTCJul 22, 00:15 UTC1h 0m
2026-07-21 CAL222 TSA → HND Jul 21, 12:00 UTCJul 21, 13:15 UTC1h 15m
2026-07-21 CAL222 TSA → HND Jul 21, 10:25 UTCJul 21, 10:30 UTC5m
2026-07-21 CAL221 HND → TSA Jul 21, 08:15 UTCJul 21, 08:25 UTC10m
2026-07-21 CAL221 HND → TSA Jul 21, 05:40 UTCJul 21, 06:40 UTC1h 0m
2026-07-21 CAL220 TSA → HND Jul 21, 02:45 UTCJul 21, 03:55 UTC1h 10m
2026-07-21 CAL220 TSA → HND Jul 21, 01:10 UTCJul 21, 01:15 UTC5m
2026-07-20 CAL202 - Jul 20, 09:35 UTCJul 20, 09:50 UTC15m
2026-07-20 CAL201 TSA → SHA Jul 20, 04:30 UTCJul 20, 05:20 UTC50m
2026-07-20 CAL223 - Jul 20, 01:35 UTCJul 20, 02:00 UTC25m
2026-07-19 CAL223 - Jul 19, 23:05 UTCJul 20, 00:05 UTC1h 0m
2026-07-19 CAL222 TSA → HND Jul 19, 10:35 UTCJul 19, 13:30 UTC2h 55m
2026-07-19 CAL221 - Jul 19, 08:15 UTCJul 19, 08:35 UTC20m
2026-07-19 CAL221 - Jul 19, 05:45 UTCJul 19, 06:50 UTC1h 5m
2026-07-19 CAL220 - Jul 19, 02:45 UTCJul 19, 04:05 UTC1h 20m
2026-07-19 CAL220 - Jul 19, 01:10 UTCJul 19, 01:25 UTC15m
2026-07-18 CAL202 TSA → TSA Jul 18, 10:00 UTCJul 18, 10:05 UTC5m
2026-07-18 CAL201 - Jul 18, 04:30 UTCJul 18, 04:45 UTC15m
2026-07-18 CAL223 - Jul 18, 01:34 UTCJul 18, 01:39 UTC5m
2026-07-17 CAL223 - Jul 17, 23:05 UTCJul 18, 00:10 UTC1h 5m
2026-07-17 CAL222 - Jul 17, 12:04 UTCJul 17, 13:20 UTC1h 15m
2026-07-17 CAL222 - Jul 17, 10:25 UTCJul 17, 10:35 UTC10m
2026-07-17 CAL221 - Jul 17, 08:10 UTCJul 17, 08:25 UTC15m
2026-07-17 CAL221 - Jul 17, 05:45 UTCJul 17, 06:45 UTC1h 0m
2026-07-17 CAL220 - Jul 17, 02:59 UTCJul 17, 04:20 UTC1h 20m
2026-07-17 CAL220 - Jul 17, 01:20 UTCJul 17, 01:35 UTC15m
2026-07-16 CAL202 - Jul 16, 10:04 UTCJul 16, 10:15 UTC10m
2026-07-16 CAL201 - Jul 16, 04:50 UTCJul 16, 05:10 UTC20m
2026-07-16 CAL223 - Jul 16, 01:30 UTCJul 16, 01:45 UTC15m
2026-07-15 CAL223 - Jul 15, 23:05 UTCJul 16, 00:05 UTC1h 0m
2026-07-15 CAL222 - Jul 15, 12:10 UTCJul 15, 13:05 UTC55m

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-18358 page for operator, model, and routing details .

Mode-S 8991AA frequently asked

What is Mode-S code 8991AA?
8991AA is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-18358.
Where is Mode-S 8991AA registered?
Mode-S code 8991AA is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8991AA broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 09:50 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8991AA, octal 42310652, decimal 9,015,722.
What flights does 8991AA operate?
Mode-S 8991AA has broadcast 20 distinct callsigns, including CAL223, CAL221, CAL222, CAL220, CAL201.