Apparatus

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sensors Mode-S transponder

8991E4

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-58501 · AIRBUS A-350-900

Hex
8991E4
Octal
42310744
Decimal
9,015,780
Country
TW
Tail
B-58501
Type
A359
No current signal · last broadcast 6h ago
Flights observed
221
Distinct callsigns
20
Country
TW
Last broadcast
6h ago

Last known position

Most recent position reported by Mode-S 8991E4.

Country allocation

The ICAO 24-bit address 8991E4 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
SJX032 STARLUX Airlines 23 2026-06-28
SJX031 - 19 2026-06-29
SJX001 - 19 2026-06-19
SJX823 - 12 2026-07-07
SJX002 - 12 2026-07-09
SJX851 - 11 2026-07-02
SJX850 - 10 2026-07-02
SJX771 - 9 2026-07-13
SJX742 - 9 2026-07-08
SJX741 - 9 2026-07-08
SJX010 - 9 2026-06-26
SJX822 - 8 2026-07-07
SJX772 - 7 2026-07-13
SJX012 - 7 2026-07-13
SJX011 - 7 2026-07-14
SJX009 - 7 2026-06-27
SJX870 - 5 2026-06-28
SJX803 - 5 2026-07-09
SJX871 - 4 2026-06-28
SJX802 - 4 2026-07-09

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 SJX011 - Jul 14, 08:40 UTCJul 14, 09:15 UTC35m
2026-07-13 SJX012 TPE → SFO Jul 13, 16:40 UTCJul 14, 05:15 UTC12h 35m
2026-07-13 SJX772 - Jul 13, 06:40 UTCJul 13, 11:00 UTC4h 20m
2026-07-13 SJX771 - Jul 13, 04:00 UTCJul 13, 04:20 UTC20m
2026-07-13 SJX771 - Jul 13, 00:25 UTCJul 13, 01:10 UTC45m
2026-07-11 SJX3001 LAX → TPE Jul 11, 06:15 UTCJul 11, 18:55 UTC12h 40m
2026-07-09 SJX002 - Jul 9, 17:15 UTCJul 10, 05:00 UTC11h 45m
2026-07-09 SJX803 NRT → TPE Jul 9, 07:50 UTCJul 9, 10:40 UTC2h 50m
2026-07-09 SJX802 - Jul 9, 03:15 UTCJul 9, 06:10 UTC2h 55m
2026-07-08 SJX742 - Jul 8, 06:45 UTCJul 8, 10:15 UTC3h 30m
2026-07-08 SJX741 TPE → BKK Jul 8, 01:50 UTCJul 8, 05:00 UTC3h 10m
2026-07-07 SJX823 - Jul 7, 08:10 UTCJul 7, 08:30 UTC20m
2026-07-07 SJX823 - Jul 7, 06:25 UTCJul 7, 07:00 UTC35m
2026-07-07 SJX822 TPE → KIX Jul 7, 02:40 UTCJul 7, 04:55 UTC2h 15m
2026-07-06 SJX803 - Jul 6, 10:20 UTCJul 6, 10:45 UTC25m
2026-07-06 SJX803 - Jul 6, 07:55 UTCJul 6, 09:10 UTC1h 15m
2026-07-06 SJX802 TPE → NRT Jul 6, 03:25 UTCJul 6, 06:20 UTC2h 55m
2026-07-05 SJX803 NRT → TPE Jul 5, 07:55 UTCJul 5, 10:45 UTC2h 50m
2026-07-05 SJX802 TPE → NRT Jul 5, 03:05 UTCJul 5, 05:55 UTC2h 50m
2026-07-04 SJX803 NRT → TPE Jul 4, 07:45 UTCJul 4, 10:40 UTC2h 55m
2026-07-04 SJX802 - Jul 4, 03:00 UTCJul 4, 05:55 UTC2h 55m
2026-07-03 SJX823 - Jul 3, 08:25 UTCJul 3, 08:50 UTC25m
2026-07-03 SJX823 - Jul 3, 06:40 UTCJul 3, 07:15 UTC35m
2026-07-03 SJX822 TPE → KIX Jul 3, 02:25 UTCJul 3, 04:55 UTC2h 30m
2026-07-02 SJX851 - Jul 2, 07:45 UTCJul 2, 11:20 UTC3h 35m
2026-07-02 SJX850 TPE → CTS Jul 2, 02:35 UTCJul 2, 05:55 UTC3h 20m
2026-07-01 SJX025 PHX → TPE Jul 1, 06:40 UTCJul 1, 20:20 UTC13h 40m
2026-06-30 SJX026 TPE → PHX Jun 30, 14:10 UTCJul 1, 00:40 UTC10h 30m
2026-06-30 SJX026 TPE → PHX Jun 30, 12:45 UTCJun 30, 13:00 UTC15m
2026-06-29 SJX031 - Jun 29, 08:24 UTCJun 29, 20:15 UTC11h 50m
2026-06-28 SJX032 TPE → SEA Jun 28, 14:04 UTCJun 28, 22:34 UTC8h 30m
2026-06-28 SJX032 TPE → SEA Jun 28, 12:39 UTCJun 28, 13:00 UTC20m
2026-06-28 SJX871 - Jun 28, 08:25 UTCJun 28, 08:39 UTC15m
2026-06-28 SJX870 - Jun 28, 04:40 UTCJun 28, 05:04 UTC25m
2026-06-27 SJX009 - Jun 27, 06:30 UTCJun 27, 19:49 UTC13h 20m
2026-06-26 SJX010 - Jun 26, 13:59 UTCJun 26, 23:44 UTC9h 45m
2026-06-26 SJX010 - Jun 26, 12:29 UTCJun 26, 12:44 UTC15m
2026-06-25 SJX031 SEA → TPE Jun 25, 08:30 UTCJun 25, 20:19 UTC11h 50m
2026-06-24 SJX032 TPE → SEA Jun 24, 21:54 UTCJun 24, 22:35 UTC40m
2026-06-24 SJX032 TPE → SEA Jun 24, 12:30 UTCJun 24, 12:44 UTC15m
2026-06-24 SJX742 - Jun 24, 06:29 UTCJun 24, 09:49 UTC3h 20m
2026-06-24 SJX741 TPE → BKK Jun 24, 01:24 UTCJun 24, 04:30 UTC3h 5m
2026-06-23 SJX031 BFI → TPE Jun 23, 08:39 UTCJun 23, 20:19 UTC11h 40m
2026-06-22 SJX032 TPE → SEA Jun 22, 13:59 UTCJun 22, 22:44 UTC8h 45m
2026-06-22 SJX032 TPE → SEA Jun 22, 12:30 UTCJun 22, 12:49 UTC20m
2026-06-21 SJX031 SEA → TPE Jun 21, 08:40 UTCJun 21, 20:05 UTC11h 25m
2026-06-20 SJX032 TPE → SEA Jun 20, 12:45 UTCJun 20, 23:19 UTC10h 35m
2026-06-19 SJX001 - Jun 19, 20:24 UTCJun 19, 20:40 UTC15m
2026-06-19 SJX001 - Jun 19, 07:54 UTCJun 19, 18:49 UTC10h 55m
2026-06-18 SJX002 - Jun 18, 16:50 UTCJun 19, 04:29 UTC11h 39m

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-58501 page for operator, model, and routing details .

Mode-S 8991E4 frequently asked

What is Mode-S code 8991E4?
8991E4 is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-58501.
Where is Mode-S 8991E4 registered?
Mode-S code 8991E4 is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8991E4 broadcasting right now?
No active broadcast right now. Last signal was 6h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8991E4, octal 42310744, decimal 9,015,780.
What flights does 8991E4 operate?
Mode-S 8991E4 has broadcast 20 distinct callsigns, including SJX032, SJX031, SJX001, SJX823, SJX002.