Apparatus

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sensors Mode-S transponder

4C01E1

ICAO 24-bit transponder address · allocated to Serbia

Currently assigned to YU-APB · AIRBUS A-319

Hex
4C01E1
Octal
23000741
Decimal
4,981,217
Country
RS
Tail
YU-APB
Type
A319
No current signal · last broadcast 25d ago
Flights observed
236
Distinct callsigns
20
Country
RS
Last broadcast
25d ago

Last known position

Most recent position reported by Mode-S 4C01E1.

Country allocation

The ICAO 24-bit address 4C01E1 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 20 distinct

Callsign Airline Flights Last seen
ASL95E - 7 2026-07-13
ASL91K - 6 2026-07-13
ASL86T - 6 2026-07-18
ASL71G - 6 2026-07-18
ASL58D - 6 2026-07-10
ASL42A - 6 2026-07-13
ASL20K - 6 2026-07-13
ASL136 - 6 2026-07-16
ASL12X - 6 2026-07-10
ASL81E Spurling Aviation 5 2026-07-26
ASL54D Spurling Aviation 5 2026-07-26
ASL130 - 5 2026-07-08
ASL94D - 4 2026-07-09
ASL19P - 4 2026-07-09
ASL122 Spurling Aviation 4 2026-07-01
ASL73B Spurling Aviation 3 2026-06-13
ASL54C - 3 2026-07-10
ASL30L - 3 2026-07-15
ASL24M - 3 2026-07-15
ASL18A - 3 2026-07-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 ASL54D BEG → PVK Jul 26, 19:25 UTCJul 26, 20:30 UTC1h 5m
2026-07-26 ASL81E BEG → FCO Jul 26, 16:30 UTCJul 26, 17:50 UTC1h 20m
2026-07-26 ASL4041 - Jul 26, 14:10 UTCJul 26, 14:45 UTC35m
2026-07-20 ASL4040 BEG → SOF Jul 20, 03:15 UTCJul 20, 03:50 UTC35m
2026-07-19 ASL44H - Jul 19, 18:40 UTCJul 19, 20:00 UTC1h 20m
2026-07-19 ASL86W BEG → BER Jul 19, 16:00 UTCJul 19, 17:30 UTC1h 30m
2026-07-19 ASL96D ATH → BEG Jul 19, 13:25 UTCJul 19, 14:45 UTC1h 20m
2026-07-19 ASL64R BEG → ATH Jul 19, 10:30 UTCJul 19, 11:40 UTC1h 10m
2026-07-19 ASL427 - Jul 19, 01:40 UTCJul 19, 02:45 UTC1h 5m
2026-07-18 ASL426 - Jul 18, 23:10 UTCJul 19, 00:20 UTC1h 10m
2026-07-18 ASL85L - Jul 18, 19:20 UTCJul 18, 21:20 UTC2h 0m
2026-07-18 ASL23Z - Jul 18, 15:30 UTCJul 18, 17:50 UTC2h 20m
2026-07-18 ASL71G - Jul 18, 08:50 UTCJul 18, 10:45 UTC1h 55m
2026-07-18 ASL86T - Jul 18, 04:50 UTCJul 18, 07:10 UTC2h 20m
2026-07-18 ASL96B - Jul 18, 02:00 UTCJul 18, 02:29 UTC30m
2026-07-17 ASL59D - Jul 17, 23:39 UTCJul 18, 00:04 UTC25m
2026-07-17 ASL65W ARN → BEG Jul 17, 19:05 UTCJul 17, 21:25 UTC2h 20m
2026-07-17 ASL82Y BEG → ARN Jul 17, 15:49 UTCJul 17, 18:05 UTC2h 15m
2026-07-17 ASL178 BEG → BEG Jul 17, 08:49 UTCJul 17, 14:30 UTC5h 40m
2026-07-17 ASL15A - Jul 17, 06:50 UTCJul 17, 07:14 UTC25m
2026-07-17 ASL57F - Jul 17, 04:54 UTCJul 17, 05:20 UTC25m
2026-07-17 ASL137 - Jul 17, 02:10 UTCJul 17, 02:50 UTC40m
2026-07-17 ASL137 - Jul 17, 00:10 UTCJul 17, 00:40 UTC30m
2026-07-16 ASL136 - Jul 16, 20:09 UTCJul 16, 22:15 UTC2h 5m
2026-07-16 ASL48X - Jul 16, 12:00 UTCJul 16, 14:20 UTC2h 20m
2026-07-16 ASL38M BEG → LCA Jul 16, 08:45 UTCJul 16, 10:50 UTC2h 5m
2026-07-16 ASL81K - Jul 16, 06:45 UTCJul 16, 07:15 UTC30m
2026-07-16 ASL84H - Jul 16, 05:10 UTCJul 16, 05:30 UTC20m
2026-07-15 ASL30L - Jul 15, 20:20 UTCJul 15, 20:50 UTC30m
2026-07-15 ASL24M - Jul 15, 18:45 UTCJul 15, 19:05 UTC20m
2026-07-15 ASL22Q TIV → BEG Jul 15, 17:05 UTCJul 15, 17:35 UTC30m
2026-07-15 ASL30D SKP → BEG Jul 15, 15:20 UTCJul 15, 15:40 UTC20m
2026-07-15 ASL71A - Jul 15, 11:25 UTCJul 15, 14:00 UTC2h 35m
2026-07-15 ASL27E BEG → MAD Jul 15, 06:35 UTCJul 15, 09:40 UTC3h 5m
2026-07-14 ASL186 BEG → GOJ Jul 14, 12:20 UTCJul 14, 20:00 UTC7h 40m
2026-07-14 ASL16G MXP → BEG Jul 14, 07:55 UTCJul 14, 09:10 UTC1h 15m
2026-07-14 ASL58V BEG → MXP Jul 14, 05:10 UTCJul 14, 06:35 UTC1h 25m
2026-07-13 ASL91K TBS → BEG Jul 13, 23:50 UTCJul 14, 02:45 UTC2h 55m
2026-07-13 ASL95E - Jul 13, 12:00 UTCJul 13, 14:40 UTC2h 40m
2026-07-13 ASL20K - Jul 13, 07:50 UTCJul 13, 09:05 UTC1h 15m
2026-07-13 ASL42A - Jul 13, 05:20 UTCJul 13, 06:25 UTC1h 5m
2026-07-12 ASL54D - Jul 12, 19:10 UTCJul 12, 20:20 UTC1h 10m
2026-07-12 ASL81E - Jul 12, 16:45 UTCJul 12, 17:55 UTC1h 10m
2026-07-12 ASL32P BEG → LCA Jul 12, 14:50 UTCJul 12, 15:15 UTC25m
2026-07-12 ASL38Y - Jul 12, 12:30 UTCJul 12, 12:55 UTC25m
2026-07-11 ASL96U LHR → BEG Jul 11, 19:20 UTCJul 11, 21:30 UTC2h 10m
2026-07-11 ASL60L BEG → LHR Jul 11, 15:05 UTCJul 11, 17:40 UTC2h 35m
2026-07-11 ASL71A MAD → BEG Jul 11, 10:50 UTCJul 11, 13:25 UTC2h 35m
2026-07-11 ASL27E BEG → MAD Jul 11, 06:20 UTCJul 11, 09:15 UTC2h 55m
2026-07-10 ASL98C ZRH → BEG Jul 10, 21:25 UTCJul 10, 22:40 UTC1h 15m

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

Mode-S 4C01E1 frequently asked

What is Mode-S code 4C01E1?
4C01E1 is an ICAO 24-bit transponder address. Allocated to Serbia. Assigned to YU-APB.
Where is Mode-S 4C01E1 registered?
Mode-S code 4C01E1 is allocated to Serbia (RS). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4C01E1 broadcasting right now?
No active broadcast right now. Last signal was 25d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4C01E1, octal 23000741, decimal 4,981,217.
What flights does 4C01E1 operate?
Mode-S 4C01E1 has broadcast 20 distinct callsigns, including ASL95E, ASL91K, ASL86T, ASL71G, ASL58D.