sensors Mode-S transponder

8991D9

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-58211 · AIRBUS A-321neo

Hex
8991D9
Octal
42310731
Decimal
9,015,769
Country
TW
Tail
B-58211
Type
A21N
Broadcasting now · callsign SJX300 · 15,900 ft
Flights observed
8
Distinct callsigns
6
Country
TW
Last broadcast
16h ago

Current position

8991D9 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 8991D9 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 6 distinct

Callsign Airline Flights Last seen
SJX313 - 2 2026-04-13
SJX312 - 2 2026-04-13
SJX328 - 1 2026-04-14
SJX316 - 1 2026-04-14
SJX307 - 1 2026-04-13
SJX306 STARLUX Airlines 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 SJX316 - Apr 14, 07:20 UTCApr 14, 08:10 UTC50m
2026-04-14 SJX328 - Apr 14, 05:15 UTCApr 14, 05:45 UTC30m
2026-04-13 SJX313 - Apr 13, 12:20 UTCApr 13, 12:30 UTC10m
2026-04-13 SJX313 - Apr 13, 12:00 UTCApr 13, 12:15 UTC15m
2026-04-13 SJX312 - Apr 13, 09:50 UTCApr 13, 10:00 UTC10m
2026-04-13 SJX312 - Apr 13, 08:50 UTCApr 13, 09:10 UTC20m
2026-04-13 SJX307 - Apr 13, 06:55 UTCApr 13, 07:25 UTC30m
2026-04-13 SJX306 RMQ → UKB Apr 13, 01:05 UTCApr 13, 01:55 UTC50m

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-58211 page for operator, model, and routing details .

Mode-S 8991D9 frequently asked

What is Mode-S code 8991D9?
8991D9 is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-58211.
Where is Mode-S 8991D9 registered?
Mode-S code 8991D9 is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8991D9 broadcasting right now?
Yes. Mode-S 8991D9 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8991D9, octal 42310731, decimal 9,015,769.
What flights does 8991D9 operate?
Mode-S 8991D9 has broadcast 6 distinct callsigns, including SJX313, SJX312, SJX328, SJX316, SJX307.