sensors Mode-S transponder

8990EF

ICAO 24-bit transponder address · allocated to Taiwan

Currently assigned to B-18777 · BOEING 777-200LR

Hex
8990EF
Octal
42310357
Decimal
9,015,535
Country
TW
Tail
B-18777
Type
B77L
No current signal · last broadcast 18h ago
Flights observed
11
Distinct callsigns
4
Country
TW
Last broadcast
18h ago

Last known position

Most recent position reported by Mode-S 8990EF.

Country allocation

The ICAO 24-bit address 8990EF 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 4 distinct

Callsign Airline Flights Last seen
CAL5236 - 5 2026-04-13
CAL5828 - 2 2026-04-13
CAL5827 China Airlines 2 2026-04-13
CAL5235 - 2 2026-04-14

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-14 CAL5235 - Apr 14, 10:00 UTCApr 14, 11:05 UTC1h 5m
2026-04-14 CAL5235 - Apr 14, 07:15 UTCApr 14, 08:55 UTC1h 40m
2026-04-13 CAL5236 - Apr 13, 21:50 UTCApr 13, 23:45 UTC1h 55m
2026-04-13 CAL5236 - Apr 13, 19:50 UTCApr 13, 20:25 UTC35m
2026-04-13 CAL5236 - Apr 13, 18:45 UTCApr 13, 20:10 UTC1h 25m
2026-04-13 CAL5236 - Apr 13, 14:05 UTCApr 13, 14:55 UTC50m
2026-04-13 CAL5236 - Apr 13, 12:20 UTCApr 13, 12:35 UTC15m
2026-04-13 CAL5828 - Apr 13, 08:25 UTCApr 13, 09:20 UTC55m
2026-04-13 CAL5828 - Apr 13, 08:00 UTCApr 13, 08:15 UTC15m
2026-04-13 CAL5827 TPE → TPE Apr 13, 04:20 UTCApr 13, 05:45 UTC1h 25m
2026-04-13 CAL5827 TPE → TPE Apr 13, 04:10 UTCApr 13, 05:45 UTC1h 35m

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-18777 page for operator, model, and routing details .

Mode-S 8990EF frequently asked

What is Mode-S code 8990EF?
8990EF is an ICAO 24-bit transponder address. Allocated to Taiwan. Assigned to B-18777.
Where is Mode-S 8990EF registered?
Mode-S code 8990EF is allocated to Taiwan (TW). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8990EF broadcasting right now?
No active broadcast right now. Last signal was 18h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8990EF, octal 42310357, decimal 9,015,535.
What flights does 8990EF operate?
Mode-S 8990EF has broadcast 4 distinct callsigns, including CAL5236, CAL5828, CAL5827, CAL5235.