Apparatus

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sensors Mode-S transponder

4D21B1

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-FHB · AIRBUS A-320

Hex
4D21B1
Octal
23220661
Decimal
5,054,897
Country
MT
Tail
9H-FHB
Type
A320
No current signal · last broadcast 1d ago
Flights observed
236
Distinct callsigns
20
Country
MT
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 4D21B1.

Country allocation

The ICAO 24-bit address 4D21B1 falls within the block assigned to Malta (MT) by ICAO Annex 10, Volume III. Every aircraft registered in Malta 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
FHM7522 - 15 2026-05-19
FHM7164 - 15 2026-05-21
FHM7140 Freebird Airlines Europe 15 2026-05-19
FHM7172 - 14 2026-05-20
FHM7316 Freebird Airlines Europe 12 2026-05-16
FHM793 - 7 2026-05-29
FHY471 - 5 2026-06-06
FHM7311 Freebird Airlines Europe 5 2026-05-15
FHM7215 - 5 2026-05-18
FHM7214 - 5 2026-05-18
FHM7161 Freebird Airlines Europe 5 2026-05-17
FHM7160 - 5 2026-05-17
FHY1528 - 4 2026-06-12
FHY1527 - 4 2026-06-12
FHM7310 Freebird Airlines Europe 4 2026-05-15
FHM687 - 4 2026-06-08
FHM1072 Freebird Airlines Europe 4 2026-06-20
FHM5141 - 3 2026-06-15
FHM1071 Freebird Airlines Europe 3 2026-06-20
TVS35K Smart Wings 2 2026-06-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 FHM5376 - Jul 13, 06:01 UTCJul 13, 09:00 UTC3h 0m
2026-07-13 FHM5375 - Jul 13, 01:35 UTCJul 13, 04:15 UTC2h 40m
2026-07-12 FHM5376 - Jul 12, 05:15 UTCJul 12, 08:15 UTC3h 0m
2026-07-12 FHM5375 - Jul 12, 01:10 UTCJul 12, 03:50 UTC2h 40m
2026-07-11 FHM5351 CGN → CGN Jul 11, 12:05 UTCJul 11, 21:20 UTC9h 15m
2026-07-10 LBT635P - Jul 10, 23:55 UTCJul 11, 01:50 UTC1h 55m
2026-07-10 LBT397 - Jul 10, 20:10 UTCJul 10, 22:20 UTC2h 10m
2026-07-10 LBT396 - Jul 10, 16:10 UTCJul 10, 18:25 UTC2h 15m
2026-07-10 LBT233 - Jul 10, 12:05 UTCJul 10, 14:10 UTC2h 5m
2026-07-10 LBT232 - Jul 10, 08:05 UTCJul 10, 10:20 UTC2h 15m
2026-07-09 LBT397 - Jul 9, 17:05 UTCJul 9, 19:05 UTC2h 0m
2026-07-09 LBT396 - Jul 9, 13:25 UTCJul 9, 15:35 UTC2h 10m
2026-07-09 LBT517 - Jul 9, 10:30 UTCJul 9, 11:40 UTC1h 10m
2026-07-09 LBT516 - Jul 9, 07:20 UTCJul 9, 08:45 UTC1h 25m
2026-07-08 LBT613 - Jul 8, 20:40 UTCJul 8, 21:50 UTC1h 10m
2026-07-08 LBT612 - Jul 8, 17:55 UTCJul 8, 19:05 UTC1h 10m
2026-07-08 LBT723 - Jul 8, 14:20 UTCJul 8, 16:15 UTC1h 55m
2026-07-08 LBT722 - Jul 8, 10:45 UTCJul 8, 12:45 UTC2h 0m
2026-07-07 LBT635 - Jul 7, 18:05 UTCJul 7, 19:25 UTC1h 20m
2026-07-07 LBT634 - Jul 7, 15:00 UTCJul 7, 16:20 UTC1h 20m
2026-07-07 LBT723 - Jul 7, 09:05 UTCJul 7, 10:55 UTC1h 50m
2026-07-06 LBT715 - Jul 6, 17:35 UTCJul 7, 07:40 UTC14h 5m
2026-07-06 LBT714 - Jul 6, 14:55 UTCJul 6, 16:10 UTC1h 15m
2026-07-06 LBT511 - Jul 6, 10:20 UTCJul 6, 12:05 UTC1h 45m
2026-07-06 LBT510 - Jul 6, 06:30 UTCJul 6, 08:40 UTC2h 10m
2026-07-05 LBT635 - Jul 5, 18:25 UTCJul 5, 19:45 UTC1h 20m
2026-07-05 LBT634 - Jul 5, 15:05 UTCJul 5, 16:35 UTC1h 30m
2026-07-05 LBT634P - Jul 5, 10:45 UTCJul 5, 12:40 UTC1h 55m
2026-07-04 LBT521P - Jul 4, 00:30 UTCJul 4, 02:35 UTC2h 5m
2026-07-03 LBT521 - Jul 3, 21:00 UTCJul 3, 22:40 UTC1h 40m
2026-07-03 LBT520 - Jul 3, 08:25 UTCJul 3, 19:30 UTC11h 5m
2026-07-02 LBT714 - Jul 2, 21:20 UTCJul 3, 06:55 UTC9h 35m
2026-07-02 LBT598 - Jul 2, 18:40 UTCJul 2, 20:05 UTC1h 25m
2026-07-02 LBT587 - Jul 2, 15:25 UTCJul 2, 16:15 UTC50m
2026-07-02 LBT586 - Jul 2, 12:40 UTCJul 2, 13:50 UTC1h 10m
2026-07-01 LBT731 - Jul 1, 15:45 UTCJul 1, 17:40 UTC1h 55m
2026-07-01 LBT730 - Jul 1, 11:00 UTCJul 1, 13:15 UTC2h 15m
2026-07-01 LBT730P - Jul 1, 07:05 UTCJul 1, 09:45 UTC2h 40m
2026-06-29 FHY222 - Jun 29, 12:55 UTCJun 29, 16:50 UTC3h 55m
2026-06-28 SDR995F - Jun 28, 19:20 UTCJun 28, 20:39 UTC1h 20m
2026-06-28 SDR8873 - Jun 28, 16:05 UTCJun 28, 18:25 UTC2h 20m
2026-06-28 SDR994F CGN → PMO Jun 28, 12:44 UTCJun 28, 14:54 UTC2h 10m
2026-06-27 FHM5351 CGN → CGN Jun 27, 11:55 UTCJun 27, 21:44 UTC9h 50m
2026-06-25 TVS132 - Jun 25, 23:05 UTCJun 26, 00:15 UTC1h 10m
2026-06-25 TVS8FK PMI → OSR Jun 25, 17:34 UTCJun 25, 22:14 UTC4h 40m
2026-06-25 TVS35K HER → OSR Jun 25, 14:14 UTCJun 25, 16:24 UTC2h 10m
2026-06-25 TVS35H OSR → HER Jun 25, 10:50 UTCJun 25, 13:00 UTC2h 10m
2026-06-25 TVS8TY AYT → OSR Jun 25, 06:44 UTCJun 25, 09:14 UTC2h 30m
2026-06-25 TVS7TY OSR → AYT Jun 25, 02:39 UTCJun 25, 05:09 UTC2h 30m
2026-06-24 TVS2103 - Jun 24, 22:39 UTCJun 25, 00:59 UTC2h 20m

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 9H-FHB page for operator, model, and routing details .

Mode-S 4D21B1 frequently asked

What is Mode-S code 4D21B1?
4D21B1 is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-FHB.
Where is Mode-S 4D21B1 registered?
Mode-S code 4D21B1 is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21B1 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21B1, octal 23220661, decimal 5,054,897.
What flights does 4D21B1 operate?
Mode-S 4D21B1 has broadcast 20 distinct callsigns, including FHM7522, FHM7164, FHM7140, FHM7172, FHM7316.