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sensors Mode-S transponder

4C4A21

ICAO 24-bit transponder address · allocated to Serbia

Currently assigned to YU-SRB · EMBRAER EMB-135 Legacy

Hex
4C4A21
Octal
23045041
Decimal
4,999,713
Country
RS
Tail
YU-SRB
Type
E35L
No current signal · last broadcast 6d ago
Flights observed
72
Distinct callsigns
1
Country
RS
Last broadcast
6d ago

Last known position

Most recent position reported by Mode-S 4C4A21.

Country allocation

The ICAO 24-bit address 4C4A21 falls within the block assigned to Serbia (RS) by ICAO Annex 10, Volume III. Every aircraft registered in Serbia 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 1 distinct

Callsign Airline Flights Last seen
YUSRB - 72 2026-07-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 YUSRB - Jul 17, 14:04 UTCJul 17, 14:30 UTC25m
2026-07-17 YUSRB - Jul 17, 13:10 UTCJul 17, 13:25 UTC15m
2026-07-17 YUSRB - Jul 17, 12:00 UTCJul 17, 12:15 UTC15m
2026-07-17 YUSRB - Jul 17, 10:50 UTCJul 17, 11:04 UTC15m
2026-07-17 YUSRB - Jul 17, 09:10 UTCJul 17, 09:30 UTC20m
2026-07-17 YUSRB - Jul 17, 07:50 UTCJul 17, 08:04 UTC15m
2026-07-16 YUSRB BTS → BEG Jul 16, 10:40 UTCJul 16, 11:30 UTC50m
2026-07-16 YUSRB BEG → BTS Jul 16, 07:15 UTCJul 16, 08:00 UTC45m
2026-07-13 YUSRB LED → BEG Jul 13, 11:10 UTCJul 13, 14:05 UTC2h 55m
2026-07-13 YUSRB - Jul 13, 04:55 UTCJul 13, 07:50 UTC2h 55m
2026-07-08 YUSRB - Jul 8, 15:40 UTCJul 8, 15:55 UTC15m
2026-07-08 YUSRB - Jul 8, 13:00 UTCJul 8, 13:50 UTC50m
2026-07-07 YUSRB LIS → BEG Jul 7, 15:15 UTCJul 7, 18:35 UTC3h 20m
2026-07-07 YUSRB BEG → LIS Jul 7, 05:25 UTCJul 7, 09:00 UTC3h 35m
2026-07-06 YUSRB - Jul 6, 12:00 UTCJul 6, 13:00 UTC1h 0m
2026-07-06 YUSRB - Jul 6, 09:25 UTCJul 6, 10:20 UTC55m
2026-07-03 YUSRB - Jul 3, 16:05 UTCJul 3, 17:50 UTC1h 45m
2026-07-02 YUSRB BEG → BRU Jul 2, 18:55 UTCJul 2, 20:55 UTC2h 0m
2026-06-30 YUSRB MUC → BEG Jun 30, 07:55 UTCJun 30, 09:05 UTC1h 10m
2026-06-30 YUSRB BEG → MUC Jun 30, 05:55 UTCJun 30, 07:05 UTC1h 10m
2026-06-27 YUSRB - Jun 27, 21:04 UTCJun 27, 22:45 UTC1h 40m
2026-06-26 YUSRB - Jun 26, 06:00 UTCJun 26, 07:39 UTC1h 40m
2026-06-25 YUSRB - Jun 25, 16:50 UTCJun 25, 18:15 UTC1h 25m
2026-06-25 YUSRB - Jun 25, 13:24 UTCJun 25, 14:59 UTC1h 35m
2026-06-25 YUSRB - Jun 25, 10:55 UTCJun 25, 12:04 UTC1h 10m
2026-06-25 YUSRB BEG → ISL Jun 25, 08:20 UTCJun 25, 09:40 UTC1h 20m
2026-06-25 YUSRB - Jun 25, 06:05 UTCJun 25, 07:05 UTC1h 0m
2026-06-25 YUSRB - Jun 25, 03:24 UTCJun 25, 05:00 UTC1h 35m
2026-06-24 YUSRB - Jun 24, 05:34 UTCJun 24, 20:35 UTC15h 0m
2026-06-23 YUSRB - Jun 23, 02:45 UTCJun 23, 03:15 UTC30m
2026-06-22 YUSRB - Jun 22, 08:25 UTCJun 22, 08:35 UTC10m
2026-06-20 YUSRB - Jun 20, 19:34 UTCJun 21, 13:39 UTC18h 5m
2026-06-17 YUSRB - Jun 17, 09:35 UTCJun 17, 12:00 UTC2h 25m
2026-06-17 YUSRB - Jun 17, 04:55 UTCJun 17, 07:15 UTC2h 20m
2026-06-16 YUSRB BER → BEG Jun 16, 08:20 UTCJun 16, 09:40 UTC1h 20m
2026-06-15 YUSRB BEG → BER Jun 15, 08:10 UTCJun 15, 09:45 UTC1h 35m
2026-06-14 YUSRB - Jun 14, 18:15 UTCJun 14, 20:50 UTC2h 35m
2026-06-14 YUSRB - Jun 14, 14:10 UTCJun 14, 16:25 UTC2h 15m
2026-06-12 YUSRB VCE → BEG Jun 12, 20:30 UTCJun 12, 21:25 UTC55m
2026-06-11 YUSRB - Jun 11, 09:30 UTCJun 11, 10:40 UTC1h 10m
2026-06-10 YUSRB SOF → BEG Jun 10, 20:35 UTCJun 10, 21:15 UTC40m
2026-06-10 YUSRB BEG → SOF Jun 10, 09:30 UTCJun 10, 10:15 UTC45m
2026-06-09 YUSRB LED → BEG Jun 9, 12:25 UTCJun 9, 15:40 UTC3h 15m
2026-06-09 YUSRB - Jun 9, 03:10 UTCJun 9, 06:05 UTC2h 55m
2026-06-06 YUSRB - Jun 6, 15:30 UTCJun 6, 16:24 UTC55m
2026-06-06 YUSRB BEG → SKG Jun 6, 13:39 UTCJun 6, 14:30 UTC50m
2026-06-03 YUSRB HEL → BEG Jun 3, 11:55 UTCJun 3, 14:30 UTC2h 35m
2026-06-03 YUSRB BEG → HEL Jun 3, 08:30 UTCJun 3, 10:55 UTC2h 25m
2026-06-01 YUSRB - Jun 1, 18:05 UTCJun 1, 18:35 UTC30m
2026-06-01 YUSRB - Jun 1, 10:10 UTCJun 1, 10:35 UTC25m

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 YU-SRB page for operator, model, and routing details .

Mode-S 4C4A21 frequently asked

What is Mode-S code 4C4A21?
4C4A21 is an ICAO 24-bit transponder address. Allocated to Serbia. Assigned to YU-SRB.
Where is Mode-S 4C4A21 registered?
Mode-S code 4C4A21 is allocated to Serbia (RS). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4C4A21 broadcasting right now?
No active broadcast right now. Last signal was 6d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4C4A21, octal 23045041, decimal 4,999,713.
What flights does 4C4A21 operate?
Mode-S 4C4A21 has broadcast 1 distinct callsign, including YUSRB.