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sensors Mode-S transponder

4D21DB

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-NEB · AIRBUS A-320neo

Hex
4D21DB
Octal
23220733
Decimal
5,054,939
Country
MT
Tail
9H-NEB
Type
A20N
No current signal · last broadcast Jul 26, 21:35 UTC
Flights observed
501
Distinct callsigns
20
Country
MT
Last broadcast
Jul 26, 21:35 UTC

Last known position

Most recent position reported by Mode-S 4D21DB.

Country allocation

The ICAO 24-bit address 4D21DB 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
KMM307 - 23 2026-07-17
KMM306 - 23 2026-07-17
KMM491 - 18 2026-07-24
KMM490 - 18 2026-07-24
KMM514 - 17 2026-07-15
KMM515 - 16 2026-07-15
KMM103 - 15 2026-07-25
KMM102 - 15 2026-07-25
KMM100A - 15 2026-07-25
KMM308 - 14 2026-07-14
KMM101 - 14 2026-07-25
KMM309 - 13 2026-07-14
KMM421 - 12 2026-07-06
KMM420 - 12 2026-07-06
KMM615 - 11 2026-07-12
KMM614 - 11 2026-07-12
KMM613 - 11 2026-06-27
KMM612 - 11 2026-06-27
KMM586 - 11 2026-07-24
KMM116 - 11 2026-07-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 KMM467 ORY → MLA Jul 26, 19:15 UTCJul 26, 21:30 UTC2h 15m
2026-07-26 KMM466 MLA → ORY Jul 26, 15:30 UTCJul 26, 18:05 UTC2h 35m
2026-07-26 KMM597 - Jul 26, 10:30 UTCJul 26, 12:35 UTC2h 5m
2026-07-26 KMM596 - Jul 26, 06:30 UTCJul 26, 09:00 UTC2h 31m
2026-07-25 KMM103 LHR → MLA Jul 25, 20:40 UTCJul 25, 23:25 UTC2h 45m
2026-07-25 KMM102 MLA → LHR Jul 25, 15:05 UTCJul 25, 18:20 UTC3h 15m
2026-07-25 KMM101 LHR → MLA Jul 25, 10:25 UTCJul 25, 12:55 UTC2h 30m
2026-07-25 KMM100A MLA → LHR Jul 25, 05:40 UTCJul 25, 08:40 UTC3h 0m
2026-07-24 KMM643 - Jul 24, 21:25 UTCJul 24, 21:50 UTC25m
2026-07-24 KMM642 - Jul 24, 19:35 UTCJul 24, 19:55 UTC20m
2026-07-24 KMM491 ZRH → MLA Jul 24, 16:35 UTCJul 24, 18:25 UTC1h 50m
2026-07-24 KMM490 MLA → ZRH Jul 24, 13:20 UTCJul 24, 15:25 UTC2h 5m
2026-07-24 KMM587 - Jul 24, 09:35 UTCJul 24, 11:35 UTC2h 0m
2026-07-24 KMM586 - Jul 24, 05:20 UTCJul 24, 07:45 UTC2h 25m
2026-07-23 KMM103 LHR → MLA Jul 23, 20:20 UTCJul 23, 23:00 UTC2h 40m
2026-07-23 KMM102 MLA → LHR Jul 23, 15:25 UTCJul 23, 18:30 UTC3h 5m
2026-07-23 KMM101 - Jul 23, 10:20 UTCJul 23, 12:50 UTC2h 30m
2026-07-23 KMM100A MLA → LHR Jul 23, 05:10 UTCJul 23, 08:35 UTC3h 25m
2026-07-22 KMM467 ORY → MLA Jul 22, 19:15 UTCJul 22, 21:30 UTC2h 15m
2026-07-22 KMM466 MLA → ORY Jul 22, 15:30 UTCJul 22, 18:05 UTC2h 35m
2026-07-22 KMM3397 - Jul 22, 11:15 UTCJul 22, 13:40 UTC2h 25m
2026-07-21 KMM3493 ZRH → MLA Jul 21, 20:40 UTCJul 21, 22:30 UTC1h 50m
2026-07-21 KMM3492 MLA → ZRH Jul 21, 14:45 UTCJul 21, 16:50 UTC2h 5m
2026-07-21 KMM423 - Jul 21, 08:25 UTCJul 21, 10:50 UTC2h 25m
2026-07-21 KMM422 MLA → BRU Jul 21, 04:10 UTCJul 21, 06:55 UTC2h 45m
2026-07-20 KMM397 AMS → MLA Jul 20, 18:15 UTCJul 20, 20:45 UTC2h 30m
2026-07-20 KMM396 MLA → AMS Jul 20, 13:30 UTCJul 20, 16:20 UTC2h 50m
2026-07-20 KMM785 - Jul 20, 08:10 UTCJul 20, 10:20 UTC2h 10m
2026-07-20 KMM784 - Jul 20, 04:10 UTCJul 20, 06:05 UTC1h 55m
2026-07-19 KMM467 ORY → MLA Jul 19, 19:15 UTCJul 19, 21:30 UTC2h 15m
2026-07-19 KMM466 MLA → ORY Jul 19, 15:20 UTCJul 19, 17:55 UTC2h 35m
2026-07-19 KMM101 LHR → MLA Jul 19, 10:20 UTCJul 19, 12:55 UTC2h 35m
2026-07-19 KMM100A MLA → LHR Jul 19, 05:10 UTCJul 19, 08:15 UTC3h 5m
2026-07-18 KMM539 PRG → MLA Jul 18, 20:00 UTCJul 18, 22:15 UTC2h 15m
2026-07-18 KMM538 MLA → PRG Jul 18, 16:30 UTCJul 18, 18:45 UTC2h 15m
2026-07-18 KMM117 LGW → MLA Jul 18, 11:35 UTCJul 18, 14:05 UTC2h 30m
2026-07-18 KMM116 MLA → LGW Jul 18, 06:40 UTCJul 18, 09:35 UTC2h 55m
2026-07-18 KMM4455 LYS → MLA Jul 18, 00:45 UTCJul 18, 02:35 UTC1h 50m
2026-07-17 KMM4454 MLA → LYS Jul 17, 22:00 UTCJul 17, 23:55 UTC1h 55m
2026-07-17 KMM3397 AMS → MLA Jul 17, 18:05 UTCJul 17, 20:40 UTC2h 35m
2026-07-17 KMM3396 MLA → AMS Jul 17, 13:29 UTCJul 17, 16:29 UTC3h 0m
2026-07-17 KMM307 MUC → MLA Jul 17, 09:15 UTCJul 17, 11:04 UTC1h 50m
2026-07-17 KMM306 - Jul 17, 05:30 UTCJul 17, 07:40 UTC2h 10m
2026-07-16 KMM103 - Jul 16, 20:45 UTCJul 16, 23:25 UTC2h 40m
2026-07-16 KMM102 MLA → LHR Jul 16, 15:40 UTCJul 16, 19:10 UTC3h 30m
2026-07-16 KMM101 LHR → MLA Jul 16, 10:10 UTCJul 16, 12:55 UTC2h 45m
2026-07-16 KMM100A MLA → LHR Jul 16, 05:10 UTCJul 16, 08:30 UTC3h 20m
2026-07-15 KMM515 VIE → MLA Jul 15, 18:00 UTCJul 15, 19:55 UTC1h 55m
2026-07-15 KMM514 MLA → VIE Jul 15, 14:55 UTCJul 15, 16:55 UTC2h 0m
2026-07-14 KMM309 MUC → MLA Jul 14, 15:45 UTCJul 14, 17:35 UTC1h 50m

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-NEB page for operator, model, and routing details .

Mode-S 4D21DB frequently asked

What is Mode-S code 4D21DB?
4D21DB is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-NEB.
Where is Mode-S 4D21DB registered?
Mode-S code 4D21DB is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21DB broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:35 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21DB, octal 23220733, decimal 5,054,939.
What flights does 4D21DB operate?
Mode-S 4D21DB has broadcast 20 distinct callsigns, including KMM307, KMM306, KMM491, KMM490, KMM514.