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
Broadcasting now · callsign FHY472 · 38,975 ft
Flights observed
127
Distinct callsigns
20
Country
MT
Last broadcast
1h ago

Current position

4D21B1 is currently broadcasting. Map zoomed to live position.

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
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
FHM7310 Freebird Airlines Europe 4 2026-05-15
FHY472 - 2 2026-05-30
FHY471 - 2 2026-05-30
FHM972 - 2 2026-05-20
FHY962 Freebird Airlines 1 2026-05-24
FHY961 - 1 2026-05-24
FHY9219 - 1 2026-05-17
FHY9216 - 1 2026-05-16
FHY9115 - 1 2026-05-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 FHY472 - May 30, 09:15 UTCMay 30, 10:15 UTC1h 0m
2026-05-30 FHY471 - May 30, 04:25 UTCMay 30, 07:55 UTC3h 30m
2026-05-29 FHY793P - May 29, 15:10 UTCMay 29, 15:35 UTC25m
2026-05-29 FHM793 - May 29, 12:15 UTCMay 29, 14:10 UTC1h 55m
2026-05-29 FHM793 - May 29, 09:05 UTCMay 29, 10:25 UTC1h 20m
2026-05-29 FHM793 - May 29, 06:10 UTCMay 29, 07:45 UTC1h 35m
2026-05-24 FHY962 HEL → HEL May 24, 08:15 UTCMay 24, 09:05 UTC50m
2026-05-24 FHY961 - May 24, 01:55 UTCMay 24, 07:10 UTC5h 15m
2026-05-23 FHY466 - May 23, 19:20 UTCMay 23, 22:15 UTC2h 55m
2026-05-23 FHY465 - May 23, 14:25 UTCMay 23, 17:35 UTC3h 10m
2026-05-23 FHY472 - May 23, 09:30 UTCMay 23, 12:50 UTC3h 20m
2026-05-23 FHY471 - May 23, 04:35 UTCMay 23, 08:00 UTC3h 25m
2026-05-22 FHM793P - May 22, 15:55 UTCMay 22, 16:20 UTC25m
2026-05-22 FHM793 - May 22, 13:10 UTCMay 22, 14:30 UTC1h 20m
2026-05-22 FHM793 - May 22, 10:15 UTCMay 22, 11:15 UTC1h 0m
2026-05-22 FHM793 - May 22, 09:55 UTCMay 22, 10:10 UTC15m
2026-05-22 FHM793 - May 22, 06:15 UTCMay 22, 08:20 UTC2h 5m
2026-05-21 FHM7164 - May 21, 11:45 UTCMay 21, 14:05 UTC2h 20m
2026-05-21 FHM7164 FRA → STR May 21, 09:50 UTCMay 21, 10:15 UTC25m
2026-05-21 FHM7164 - May 21, 05:55 UTCMay 21, 07:45 UTC1h 50m
2026-05-21 FHM973P - May 21, 02:45 UTCMay 21, 04:30 UTC1h 45m
2026-05-20 FHM973 - May 20, 16:40 UTCMay 20, 18:40 UTC2h 0m
2026-05-20 FHM972 - May 20, 14:50 UTCMay 20, 15:05 UTC15m
2026-05-20 FHM972 - May 20, 11:50 UTCMay 20, 13:45 UTC1h 55m
2026-05-20 FHM7172 BER → HAJ May 20, 09:05 UTCMay 20, 09:35 UTC30m
2026-05-20 FHM7172 - May 20, 05:55 UTCMay 20, 07:45 UTC1h 50m
2026-05-19 FHM7522 - May 19, 17:50 UTCMay 19, 20:00 UTC2h 10m
2026-05-19 FHM7522 - May 19, 16:05 UTCMay 19, 16:30 UTC25m
2026-05-19 FHM7522 - May 19, 12:50 UTCMay 19, 14:50 UTC2h 0m
2026-05-19 FHM7140 STR → MUC May 19, 10:15 UTCMay 19, 11:15 UTC1h 0m
2026-05-19 FHM7140 STR → MUC May 19, 08:25 UTCMay 19, 09:10 UTC45m
2026-05-19 FHM7140 STR → MUC May 19, 06:05 UTCMay 19, 07:25 UTC1h 20m
2026-05-18 FHM7215 - May 18, 09:40 UTCMay 18, 11:40 UTC2h 0m
2026-05-18 FHM7214 - May 18, 05:50 UTCMay 18, 08:05 UTC2h 15m
2026-05-17 FHY9219 - May 17, 14:40 UTCMay 17, 23:35 UTC8h 55m
2026-05-17 FHM7161 DUS → DUS May 17, 09:40 UTCMay 17, 11:30 UTC1h 50m
2026-05-17 FHM7160 - May 17, 06:10 UTCMay 17, 08:20 UTC2h 10m
2026-05-16 FHY9216 - May 16, 14:35 UTCMay 16, 23:15 UTC8h 40m
2026-05-16 FHM7316 MRS → LYS May 16, 10:50 UTCMay 16, 12:11 UTC1h 20m
2026-05-16 FHM7316 MRS → LYS May 16, 09:01 UTCMay 16, 09:40 UTC40m
2026-05-16 FHM7316 MRS → LYS May 16, 06:01 UTCMay 16, 08:01 UTC2h 0m
2026-05-15 FHY9115 - May 15, 14:45 UTCMay 15, 23:45 UTC8h 59m
2026-05-15 FHM7311 CDG → CDG May 15, 09:55 UTCMay 15, 11:50 UTC1h 55m
2026-05-15 FHM7310 SKP → SKP May 15, 05:45 UTCMay 15, 08:05 UTC2h 20m
2026-05-14 FHY9113 - May 14, 14:50 UTCMay 15, 00:15 UTC9h 25m
2026-05-14 FHM7164 - May 14, 11:10 UTCMay 14, 12:40 UTC1h 30m
2026-05-14 FHM7164 FRA → STR May 14, 09:25 UTCMay 14, 09:50 UTC25m
2026-05-14 FHM7164 - May 14, 05:45 UTCMay 14, 07:45 UTC2h 0m
2026-05-13 FHM7172 - May 13, 11:45 UTCMay 13, 13:20 UTC1h 35m
2026-05-13 FHM7172 - May 13, 09:45 UTCMay 13, 10:20 UTC35m

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?
Yes. Mode-S 4D21B1 is currently airborne.
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.