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sensors Mode-S transponder

4BAB21

ICAO 24-bit transponder address · allocated to Turkey

Currently assigned to TC-JYA · BOEING 737-900

Hex
4BAB21
Octal
22725441
Decimal
4,959,009
Country
TR
Tail
TC-JYA
Type
B739
Broadcasting now · callsign THY4MZ · 5,850 ft
Flights observed
301
Distinct callsigns
20
Country
TR
Last broadcast
13d ago

Current position

4BAB21 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4BAB21 falls within the block assigned to Turkey (TR) by ICAO Annex 10, Volume III. Every aircraft registered in Turkey 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
THY1VN - 9 2026-07-05
THY1140 - 9 2026-07-21
THY1139 Turkish Airlines 9 2026-07-21
THY9QS - 8 2026-07-05
THY641 - 6 2026-07-13
THY4AV - 6 2026-06-27
THY8CJ - 5 2026-07-14
THY6BW - 5 2026-07-12
THY4YM - 5 2026-07-14
THY9GY - 4 2026-06-14
THY8RJ - 4 2026-05-12
THY8GS - 4 2026-06-27
THY642 - 4 2026-07-13
THY4GL Turkish Airlines 4 2026-06-14
THY2XK - 4 2026-07-15
THY7SP - 3 2026-06-19
THY6QV - 3 2026-07-16
THY5VQ - 3 2026-07-12
THY2LJ - 3 2026-07-16
THY2GS Turkish Airlines 3 2026-05-28

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 THY6FD IST → CPH Jul 26, 17:10 UTCJul 26, 20:25 UTC3h 15m
2026-07-26 THY395 BUS → IST Jul 26, 14:50 UTCJul 26, 15:05 UTC15m
2026-07-26 THY395 BUS → IST Jul 26, 13:15 UTCJul 26, 13:55 UTC40m
2026-07-26 THY394 IST → BUS Jul 26, 10:05 UTCJul 26, 11:45 UTC1h 40m
2026-07-26 THY8FB IST → VAN Jul 26, 07:10 UTCJul 26, 08:15 UTC1h 5m
2026-07-26 THY7NU MLX → IST Jul 26, 04:55 UTCJul 26, 06:00 UTC1h 5m
2026-07-25 THY1148 MRA → IST Jul 25, 17:05 UTCJul 25, 19:20 UTC2h 15m
2026-07-25 THY1147 IST → MRA Jul 25, 12:40 UTCJul 25, 14:50 UTC2h 10m
2026-07-25 THY9NS HAM → IST Jul 25, 05:20 UTCJul 25, 08:05 UTC2h 45m
2026-07-24 THY91B IST → HAM Jul 24, 16:25 UTCJul 24, 19:10 UTC2h 45m
2026-07-24 THY17V - Jul 24, 13:25 UTCJul 24, 14:45 UTC1h 20m
2026-07-24 THY5TD AYT → BER Jul 24, 11:00 UTCJul 24, 12:15 UTC1h 15m
2026-07-24 THY7AY ASR → IST Jul 24, 05:40 UTCJul 24, 09:05 UTC3h 25m
2026-07-23 THY3XM - Jul 23, 14:15 UTCJul 23, 17:35 UTC3h 20m
2026-07-23 THY8HP GOT → IST Jul 23, 08:30 UTCJul 23, 11:25 UTC2h 55m
2026-07-23 THY9XN IST → GOT Jul 23, 04:10 UTCJul 23, 07:10 UTC3h 0m
2026-07-22 THY3TS - Jul 22, 19:20 UTCJul 22, 19:55 UTC35m
2026-07-22 THY5KA IST → BER Jul 22, 17:35 UTCJul 22, 18:10 UTC35m
2026-07-21 THY1140 - Jul 21, 18:10 UTCJul 21, 20:10 UTC2h 0m
2026-07-21 THY1139 IST → MJI Jul 21, 13:10 UTCJul 21, 15:35 UTC2h 25m
2026-07-21 THY8ED IST → CDG Jul 21, 08:30 UTCJul 21, 10:25 UTC1h 55m
2026-07-21 THY6CF STR → IST Jul 21, 05:15 UTCJul 21, 07:25 UTC2h 10m
2026-07-20 THY9WY DLM → IST Jul 20, 15:30 UTCJul 20, 16:30 UTC1h 0m
2026-07-20 THY4VB - Jul 20, 13:30 UTCJul 20, 14:10 UTC40m
2026-07-20 THY6WQ VNO → IST Jul 20, 08:45 UTCJul 20, 11:15 UTC2h 30m
2026-07-20 THY6XK IST → VNO Jul 20, 05:15 UTCJul 20, 07:25 UTC2h 10m
2026-07-19 THY6YB BAL → IST Jul 19, 18:20 UTCJul 19, 20:20 UTC2h 0m
2026-07-19 THY5BJ IST → MLX Jul 19, 14:50 UTCJul 19, 16:45 UTC1h 55m
2026-07-19 THY6NJ IST → MXP Jul 19, 11:55 UTCJul 19, 13:05 UTC1h 10m
2026-07-19 THY3DB - Jul 19, 09:35 UTCJul 19, 10:00 UTC25m
2026-07-18 THY3SF - Jul 18, 12:30 UTCJul 18, 15:55 UTC3h 25m
2026-07-17 THY7VM - Jul 17, 19:05 UTCJul 17, 20:44 UTC1h 40m
2026-07-17 THY6VU - Jul 17, 15:44 UTCJul 17, 17:25 UTC1h 40m
2026-07-17 THY6HL - Jul 17, 08:45 UTCJul 17, 10:55 UTC2h 10m
2026-07-17 THY9VT ESB → IGD Jul 17, 05:15 UTCJul 17, 07:35 UTC2h 20m
2026-07-16 THY2LJ - Jul 16, 20:49 UTCJul 16, 21:10 UTC20m
2026-07-16 THY2LJ - Jul 16, 19:40 UTCJul 16, 20:15 UTC35m
2026-07-16 THY6QV - Jul 16, 18:19 UTCJul 16, 18:34 UTC15m
2026-07-16 THY6QV - Jul 16, 17:14 UTCJul 16, 17:49 UTC35m
2026-07-16 THY8LQ - Jul 16, 12:49 UTCJul 16, 15:30 UTC2h 40m
2026-07-16 THY60S - Jul 16, 08:15 UTCJul 16, 11:25 UTC3h 10m
2026-07-15 THY1HU - Jul 15, 23:25 UTCJul 16, 02:35 UTC3h 10m
2026-07-15 THY2XK - Jul 15, 16:00 UTCJul 15, 19:40 UTC3h 40m
2026-07-15 THY4AW - Jul 15, 03:55 UTCJul 15, 07:10 UTC3h 15m
2026-07-14 THY8CJ - Jul 14, 20:20 UTCJul 14, 21:50 UTC1h 30m
2026-07-14 THY4YM - Jul 14, 16:40 UTCJul 14, 18:35 UTC1h 55m
2026-07-14 THY4ZX - Jul 14, 11:15 UTCJul 14, 13:15 UTC2h 0m
2026-07-14 THY6DR - Jul 14, 07:30 UTCJul 14, 09:45 UTC2h 15m
2026-07-13 THY1140 - Jul 13, 17:45 UTCJul 13, 20:00 UTC2h 15m
2026-07-13 THY1139 - Jul 13, 13:05 UTCJul 13, 15:30 UTC2h 25m

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 TC-JYA page for operator, model, and routing details .

Mode-S 4BAB21 frequently asked

What is Mode-S code 4BAB21?
4BAB21 is an ICAO 24-bit transponder address. Allocated to Turkey. Assigned to TC-JYA.
Where is Mode-S 4BAB21 registered?
Mode-S code 4BAB21 is allocated to Turkey (TR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4BAB21 broadcasting right now?
Yes. Mode-S 4BAB21 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4BAB21, octal 22725441, decimal 4,959,009.
What flights does 4BAB21 operate?
Mode-S 4BAB21 has broadcast 20 distinct callsigns, including THY1VN, THY1140, THY1139, THY9QS, THY641.