sensors Mode-S transponder

8990A6

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-18781 · BOEING 777-200LR

Hex
8990A6
Octal
42310246
Decimal
9,015,462
Country
TW
Tail
B-18781
Type
B77L
Broadcasting now · callsign CAL5138 · 35,000 ft
Flights observed
9
Distinct callsigns
3
Country
TW
Last broadcast
15h ago

Current position

8990A6 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 8990A6 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 3 distinct

Callsign Airline Flights Last seen
CAL5154 - 4 2026-04-13
CAL5153 - 3 2026-04-14
CAL5522 China Airlines 2 2026-04-13

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-14 CAL5153 - Apr 14, 10:55 UTCApr 14, 11:05 UTC10m
2026-04-14 CAL5153 - Apr 14, 07:25 UTCApr 14, 08:10 UTC45m
2026-04-13 CAL5153 - Apr 13, 20:50 UTCApr 13, 21:55 UTC1h 5m
2026-04-13 CAL5154 - Apr 13, 16:15 UTCApr 13, 17:40 UTC1h 25m
2026-04-13 CAL5154 - Apr 13, 08:20 UTCApr 13, 08:40 UTC20m
2026-04-13 CAL5154 - Apr 13, 08:00 UTCApr 13, 08:15 UTC15m
2026-04-13 CAL5154 - Apr 13, 06:05 UTCApr 13, 06:15 UTC10m
2026-04-13 CAL5522 FRA → TPE Apr 13, 01:50 UTCApr 13, 02:50 UTC1h 0m
2026-04-12 CAL5522 FRA → TPE Apr 12, 17:15 UTCApr 12, 18:00 UTC45m

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-18781 page for operator, model, and routing details .

Mode-S 8990A6 frequently asked

What is Mode-S code 8990A6?
8990A6 is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-18781.
Where is Mode-S 8990A6 registered?
Mode-S code 8990A6 is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8990A6 broadcasting right now?
Yes. Mode-S 8990A6 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8990A6, octal 42310246, decimal 9,015,462.
What flights does 8990A6 operate?
Mode-S 8990A6 has broadcast 3 distinct callsigns, including CAL5154, CAL5153, CAL5522.