sensors Mode-S transponder

8990A9

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-18617 · BOEING 737-800

Hex
8990A9
Octal
42310251
Decimal
9,015,465
Country
TW
Tail
B-18617
Type
B738
No current signal · last broadcast 19h ago
Flights observed
8
Distinct callsigns
5
Country
TW
Last broadcast
19h ago

Last known position

Most recent position reported by Mode-S 8990A9.

Country allocation

The ICAO 24-bit address 8990A9 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 5 distinct

Callsign Airline Flights Last seen
CAL910 China Airlines 2 2026-04-14
CAL790 - 2 2026-04-13
CAL189 - 2 2026-04-13
CAL789 - 1 2026-04-13
CAL188 China Airlines 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 CAL910 HKG → TPE Apr 14, 07:10 UTCApr 14, 07:40 UTC30m
2026-04-14 CAL910 HKG → TPE Apr 14, 06:15 UTCApr 14, 07:10 UTC55m
2026-04-13 CAL790 - Apr 13, 12:20 UTCApr 13, 12:55 UTC35m
2026-04-13 CAL790 - Apr 13, 12:00 UTCApr 13, 12:10 UTC10m
2026-04-13 CAL789 - Apr 13, 06:55 UTCApr 13, 07:50 UTC55m
2026-04-13 CAL189 - Apr 13, 05:00 UTCApr 13, 05:25 UTC25m
2026-04-13 CAL189 - Apr 13, 03:35 UTCApr 13, 03:50 UTC15m
2026-04-13 CAL188 TPE → PUS Apr 13, 00:20 UTCApr 13, 00:40 UTC20m

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-18617 page for operator, model, and routing details .

Mode-S 8990A9 frequently asked

What is Mode-S code 8990A9?
8990A9 is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-18617.
Where is Mode-S 8990A9 registered?
Mode-S code 8990A9 is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8990A9 broadcasting right now?
No active broadcast right now. Last signal was 19h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8990A9, octal 42310251, decimal 9,015,465.
What flights does 8990A9 operate?
Mode-S 8990A9 has broadcast 5 distinct callsigns, including CAL910, CAL790, CAL189, CAL789, CAL188.