Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

4C0177

ICAO 24-bit transponder address · allocated to Serbia

Currently assigned to YU-ALX · ATR-72-600

Hex
4C0177
Octal
23000567
Decimal
4,981,111
Country
RS
Tail
YU-ALX
Type
AT76
Broadcasting now · callsign ASL80A · 18,000 ft
Flights observed
412
Distinct callsigns
20
Country
RS
Last broadcast
Jul 26, 20:25 UTC

Current position

4C0177 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4C0177 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
ASL2428 Spurling Aviation 13 2026-07-25
ASL78V Spurling Aviation 12 2026-07-25
ASL2429 Spurling Aviation 12 2026-07-25
ASL36C - 11 2026-07-25
ASL18R - 11 2026-06-19
ASL78U - 10 2026-06-19
ASL26X Spurling Aviation 10 2026-07-26
ASL72L Spurling Aviation 9 2026-07-24
ASL47P Spurling Aviation 9 2026-07-26
ASL10N Spurling Aviation 9 2026-07-24
ASL51D Spurling Aviation 8 2026-07-24
ASL30J - 8 2026-07-24
ASL57F Spurling Aviation 7 2026-06-03
ASL47G - 7 2026-07-16
ASL33J - 7 2026-07-17
ASL15A Spurling Aviation 7 2026-06-03
ASL92Z - 6 2026-07-23
ASL81C Spurling Aviation 6 2026-06-07
ASL77L - 6 2026-06-15
ASL49H Spurling Aviation 6 2026-06-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 ASL48G GOT → BEG Jul 26, 18:45 UTCJul 26, 20:20 UTC1h 35m
2026-07-26 ASL95Q BEG → BLQ Jul 26, 15:40 UTCJul 26, 17:30 UTC1h 50m
2026-07-26 ASL47P SOF → BEG Jul 26, 14:10 UTCJul 26, 14:20 UTC10m
2026-07-26 ASL26X BEG → SOF Jul 26, 11:40 UTCJul 26, 12:25 UTC45m
2026-07-25 ASL36C - Jul 25, 18:35 UTCJul 25, 18:50 UTC15m
2026-07-25 ASL31A BEG → LJU Jul 25, 16:45 UTCJul 25, 17:40 UTC55m
2026-07-25 ASL77A BEG → HAJ Jul 25, 15:00 UTCJul 25, 15:45 UTC45m
2026-07-25 ASL2429 IST → KVO Jul 25, 12:15 UTCJul 25, 13:40 UTC1h 25m
2026-07-25 ASL2428 KVO → IST Jul 25, 08:45 UTCJul 25, 10:30 UTC1h 45m
2026-07-25 ASL78V FCO → BEG Jul 25, 07:05 UTCJul 25, 07:15 UTC10m
2026-07-25 ASL40B OHD → BEG Jul 25, 01:45 UTCJul 25, 02:45 UTC1h 0m
2026-07-24 ASL96P TIV → BEG Jul 24, 23:20 UTCJul 25, 00:10 UTC50m
2026-07-24 ASL10N LJU → BEG Jul 24, 18:45 UTCJul 24, 19:50 UTC1h 5m
2026-07-24 ASL72L BEG → TIA Jul 24, 16:50 UTCJul 24, 18:00 UTC1h 10m
2026-07-24 ASL51D ZAG → BEG Jul 24, 14:25 UTCJul 24, 15:20 UTC55m
2026-07-24 ASL30J - Jul 24, 12:05 UTCJul 24, 12:55 UTC50m
2026-07-24 ASL157 KRK → BEG Jul 24, 09:30 UTCJul 24, 11:00 UTC1h 30m
2026-07-24 ASL156 BEG → KRK Jul 24, 04:50 UTCJul 24, 06:20 UTC1h 30m
2026-07-24 ASL52D VAR → BEG Jul 24, 01:50 UTCJul 24, 03:15 UTC1h 25m
2026-07-23 ASL70Z PRG → BEG Jul 23, 23:25 UTCJul 24, 00:45 UTC1h 20m
2026-07-23 ASL47F PRG → BEG Jul 23, 19:50 UTCJul 23, 21:25 UTC1h 35m
2026-07-23 ASL89R BEG → PRG Jul 23, 17:05 UTCJul 23, 18:55 UTC1h 50m
2026-07-23 ASL33K - Jul 23, 13:40 UTCJul 23, 14:15 UTC35m
2026-07-23 ASL79Y - Jul 23, 11:45 UTCJul 23, 12:20 UTC35m
2026-07-23 ASL45B - Jul 23, 08:00 UTCJul 23, 08:50 UTC50m
2026-07-23 ASL92Z - Jul 23, 05:55 UTCJul 23, 06:50 UTC55m
2026-07-22 ASL37Z VIE → BEG Jul 22, 19:00 UTCJul 22, 20:05 UTC1h 5m
2026-07-22 ASL45T BEG → VIE Jul 22, 16:50 UTCJul 22, 18:05 UTC1h 15m
2026-07-22 ASL62A - Jul 22, 13:35 UTCJul 22, 14:40 UTC1h 5m
2026-07-22 ASL84P BEG → RJK Jul 22, 11:15 UTCJul 22, 12:35 UTC1h 20m
2026-07-21 ASL36C - Jul 21, 18:50 UTCJul 21, 19:20 UTC30m
2026-07-21 ASL31A BEG → LJU Jul 21, 17:05 UTCJul 21, 18:05 UTC1h 0m
2026-07-21 ASL77A BEG → HAJ Jul 21, 15:05 UTCJul 21, 16:00 UTC55m
2026-07-21 ASL2428 KVO → IST Jul 21, 11:55 UTCJul 21, 14:00 UTC2h 5m
2026-07-21 ASL2428 KVO → IST Jul 21, 08:40 UTCJul 21, 10:20 UTC1h 40m
2026-07-21 ASL78V FCO → BEG Jul 21, 07:30 UTCJul 21, 07:55 UTC25m
2026-07-19 ASL10N LJU → BEG Jul 19, 19:15 UTCJul 19, 20:30 UTC1h 15m
2026-07-19 ASL72L BEG → TIA Jul 19, 17:00 UTCJul 19, 18:35 UTC1h 35m
2026-07-17 ASL12C BNX → BEG Jul 17, 10:00 UTCJul 17, 10:35 UTC35m
2026-07-17 ASL62B - Jul 17, 08:25 UTCJul 17, 08:59 UTC35m
2026-07-17 ASL45B - Jul 17, 06:25 UTCJul 17, 07:20 UTC55m
2026-07-17 ASL92Z - Jul 17, 04:35 UTCJul 17, 05:25 UTC50m
2026-07-17 ASL33J - Jul 17, 01:55 UTCJul 17, 02:39 UTC45m
2026-07-16 ASL47G - Jul 16, 23:05 UTCJul 16, 23:44 UTC40m
2026-07-15 ASL62A - Jul 15, 13:35 UTCJul 15, 14:40 UTC1h 5m
2026-07-15 ASL84P BEG → RJK Jul 15, 11:15 UTCJul 15, 12:25 UTC1h 10m
2026-07-15 ASL33J - Jul 15, 02:10 UTCJul 15, 02:40 UTC30m
2026-07-14 ASL47G - Jul 14, 23:50 UTCJul 15, 00:35 UTC45m
2026-07-13 ASL37Z - Jul 13, 19:45 UTCJul 13, 20:45 UTC1h 0m
2026-07-13 ASL45T BEG → VIE Jul 13, 17:40 UTCJul 13, 18:55 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-ALX page for operator, model, and routing details .

Mode-S 4C0177 frequently asked

What is Mode-S code 4C0177?
4C0177 is an ICAO 24-bit transponder address. Allocated to Serbia. Assigned to YU-ALX.
Where is Mode-S 4C0177 registered?
Mode-S code 4C0177 is allocated to Serbia (RS). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4C0177 broadcasting right now?
Yes. Mode-S 4C0177 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4C0177, octal 23000567, decimal 4,981,111.
What flights does 4C0177 operate?
Mode-S 4C0177 has broadcast 20 distinct callsigns, including ASL2428, ASL78V, ASL2429, ASL36C, ASL18R.