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 Jul 26, 18:05 UTC
Flights observed
274
Distinct callsigns
20
Country
MT
Last broadcast
Jul 26, 18:05 UTC

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
FHM5376 - 7 2026-07-26
FHM5375 - 7 2026-07-26
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
FHM5362 - 4 2026-07-26
FHM5361 - 4 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 FHM5362 - Jul 26, 15:00 UTCJul 26, 18:05 UTC3h 5m
2026-07-26 FHM5361 CGN → KGS Jul 26, 11:10 UTCJul 26, 13:50 UTC2h 40m
2026-07-26 FHM5376 - Jul 26, 05:20 UTCJul 26, 08:35 UTC3h 16m
2026-07-26 FHM5375 - Jul 26, 01:25 UTCJul 26, 04:00 UTC2h 35m
2026-07-25 FHM5352 CGN → CGN Jul 25, 11:45 UTCJul 25, 22:00 UTC10h 15m
2026-07-25 FHM5346 RHO → CGN Jul 25, 07:05 UTCJul 25, 10:20 UTC3h 15m
2026-07-25 FHM5345 - Jul 25, 02:35 UTCJul 25, 05:20 UTC2h 45m
2026-07-24 FHY458 CGN → CGN Jul 24, 11:20 UTCJul 24, 19:35 UTC8h 15m
2026-07-24 FHM5362 KGS → CGN Jul 24, 06:05 UTCJul 24, 09:15 UTC3h 10m
2026-07-24 FHM5361 CGN → KGS Jul 24, 02:20 UTCJul 24, 04:55 UTC2h 35m
2026-07-23 FHM5376 - Jul 23, 15:50 UTCJul 23, 18:55 UTC3h 5m
2026-07-23 FHM5375 - Jul 23, 11:35 UTCJul 23, 14:10 UTC2h 35m
2026-07-23 FHM5346 RHO → CGN Jul 23, 06:50 UTCJul 23, 10:10 UTC3h 20m
2026-07-23 FHM5345 CGN → RHO Jul 23, 02:55 UTCJul 23, 05:45 UTC2h 50m
2026-07-22 FHY455 - Jul 22, 11:15 UTCJul 22, 19:20 UTC8h 5m
2026-07-22 FHY419 CGN → TZX Jul 22, 01:30 UTCJul 22, 04:45 UTC3h 15m
2026-07-21 FHY452 CGN → CGN Jul 21, 13:20 UTCJul 21, 21:00 UTC7h 40m
2026-07-21 FHM5346 RHO → CGN Jul 21, 08:05 UTCJul 21, 11:20 UTC3h 15m
2026-07-21 FHM5345 CGN → RHO Jul 21, 04:05 UTCJul 21, 06:55 UTC2h 50m
2026-07-20 FHM5362 KGS → CGN Jul 20, 15:30 UTCJul 20, 18:35 UTC3h 5m
2026-07-20 FHM5361 CGN → KGS Jul 20, 11:15 UTCJul 20, 14:10 UTC2h 55m
2026-07-20 FHM5376 - Jul 20, 05:55 UTCJul 20, 08:55 UTC3h 0m
2026-07-20 FHM5375 - Jul 20, 01:55 UTCJul 20, 04:30 UTC2h 35m
2026-07-19 FHM5362 KGS → CGN Jul 19, 15:20 UTCJul 19, 18:20 UTC3h 0m
2026-07-19 FHM5361 CGN → KGS Jul 19, 11:10 UTCJul 19, 13:55 UTC2h 45m
2026-07-19 FHM5376 - Jul 19, 05:35 UTCJul 19, 08:30 UTC2h 55m
2026-07-19 FHM5375 - Jul 19, 01:30 UTCJul 19, 04:10 UTC2h 40m
2026-07-18 FHM5352 - Jul 18, 18:10 UTCJul 18, 21:50 UTC3h 40m
2026-07-18 FHM5351 - Jul 18, 12:10 UTCJul 18, 16:05 UTC3h 55m
2026-07-18 FHM5346 RHO → CGN Jul 18, 07:00 UTCJul 18, 10:15 UTC3h 15m
2026-07-18 FHM5345 CGN → RHO Jul 18, 02:50 UTCJul 18, 05:45 UTC2h 55m
2026-07-17 FHY458 CGN → CGN Jul 17, 17:05 UTCJul 18, 00:50 UTC7h 45m
2026-07-17 FHM875P - Jul 17, 13:05 UTCJul 17, 13:25 UTC20m
2026-07-17 FHM875 - Jul 17, 10:30 UTCJul 17, 12:25 UTC1h 55m
2026-07-17 FHM876 - Jul 17, 06:54 UTCJul 17, 08:40 UTC1h 45m
2026-07-17 FHM876P CGN → GKE Jul 17, 05:50 UTCJul 17, 06:10 UTC20m
2026-07-16 FHM5376 - Jul 16, 15:40 UTCJul 16, 18:50 UTC3h 10m
2026-07-16 FHM5375 - Jul 16, 11:34 UTCJul 16, 14:05 UTC2h 30m
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

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 Jul 26, 18:05 UTC.
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.