Apparatus

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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
Broadcasting now · callsign KMM479 · 39,000 ft
Flights observed
449
Distinct callsigns
20
Country
MT
Last broadcast
2h ago

Current position

4D21DB is currently broadcasting. Map zoomed to live position.

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 - 22 2026-07-13
KMM306 - 22 2026-07-13
KMM491 - 17 2026-07-13
KMM490 - 17 2026-07-13
KMM514 - 16 2026-07-11
KMM515 - 15 2026-07-11
KMM308 - 13 2026-06-20
KMM421 - 12 2026-07-06
KMM420 - 12 2026-07-06
KMM309 - 12 2026-06-20
KMM103 - 12 2026-07-04
KMM102 - 12 2026-07-04
KMM615 - 11 2026-07-12
KMM614 - 11 2026-07-12
KMM613 - 11 2026-06-27
KMM612 - 11 2026-06-27
KMM100A - 11 2026-07-06
KMM625 - 10 2026-07-03
KMM624 - 10 2026-07-03
KMM586 - 10 2026-06-29

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 KMM478 MLA → CDG Jul 14, 04:10 UTCJul 14, 06:50 UTC2h 40m
2026-07-13 KMM643 - Jul 13, 21:10 UTCJul 13, 21:35 UTC25m
2026-07-13 KMM642 - Jul 13, 19:35 UTCJul 13, 20:00 UTC25m
2026-07-13 KMM491 ZRH → MLA Jul 13, 16:45 UTCJul 13, 18:30 UTC1h 45m
2026-07-13 KMM490 MLA → ZRH Jul 13, 13:25 UTCJul 13, 15:30 UTC2h 5m
2026-07-13 KMM307 MUC → MLA Jul 13, 09:30 UTCJul 13, 11:15 UTC1h 45m
2026-07-13 KMM306 MLA → MUC Jul 13, 05:10 UTCJul 13, 07:10 UTC2h 0m
2026-07-12 KMM615 FCO → MLA Jul 12, 22:05 UTCJul 12, 23:00 UTC55m
2026-07-12 KMM614 - Jul 12, 19:35 UTCJul 12, 20:45 UTC1h 10m
2026-07-12 KMM477 ORY → MLA Jul 12, 15:55 UTCJul 12, 18:05 UTC2h 10m
2026-07-12 KMM476 MLA → ORY Jul 12, 11:55 UTCJul 12, 14:30 UTC2h 35m
2026-07-12 KMM353 - Jul 12, 08:20 UTCJul 12, 10:35 UTC2h 15m
2026-07-12 KMM352 - Jul 12, 04:25 UTCJul 12, 07:10 UTC2h 45m
2026-07-11 KMM467 ORY → MLA Jul 11, 19:15 UTCJul 11, 21:35 UTC2h 20m
2026-07-11 KMM466 MLA → ORY Jul 11, 15:20 UTCJul 11, 17:50 UTC2h 30m
2026-07-11 KMM515 VIE → MLA Jul 11, 10:35 UTCJul 11, 12:35 UTC2h 0m
2026-07-11 KMM514 MLA → VIE Jul 11, 07:15 UTCJul 11, 09:15 UTC2h 0m
2026-07-11 KMM641 - Jul 11, 05:40 UTCJul 11, 06:05 UTC25m
2026-07-11 KMM640 - Jul 11, 04:05 UTCJul 11, 04:30 UTC25m
2026-07-10 KMM107 LHR → MLA Jul 10, 18:35 UTCJul 10, 21:20 UTC2h 45m
2026-07-10 KMM106 MLA → LHR Jul 10, 13:45 UTCJul 10, 16:40 UTC2h 55m
2026-07-10 KMM307 MUC → MLA Jul 10, 09:20 UTCJul 10, 11:10 UTC1h 50m
2026-07-10 KMM306 MLA → MUC Jul 10, 05:20 UTCJul 10, 07:15 UTC1h 55m
2026-07-09 KMM539 PRG → MLA Jul 9, 19:30 UTCJul 9, 21:30 UTC2h 0m
2026-07-09 KMM538 MLA → PRG Jul 9, 16:10 UTCJul 9, 18:35 UTC2h 25m
2026-07-09 KMM117 LGW → MLA Jul 9, 11:10 UTCJul 9, 13:55 UTC2h 45m
2026-07-09 KMM116 MLA → LGW Jul 9, 06:30 UTCJul 9, 09:20 UTC2h 50m
2026-07-08 KMM377 - Jul 8, 19:15 UTCJul 8, 21:30 UTC2h 15m
2026-07-08 KMM376 MLA → BER Jul 8, 15:25 UTCJul 8, 18:10 UTC2h 45m
2026-07-08 KMM117 LGW → MLA Jul 8, 11:10 UTCJul 8, 13:50 UTC2h 40m
2026-07-08 KMM116 MLA → LGW Jul 8, 06:30 UTCJul 8, 09:25 UTC2h 55m
2026-07-07 KMM3117 LGW → MLA Jul 7, 16:35 UTCJul 7, 19:10 UTC2h 35m
2026-07-07 KMM3116 MLA → LGW Jul 7, 12:05 UTCJul 7, 15:00 UTC2h 55m
2026-07-07 KMM423 - Jul 7, 08:30 UTCJul 7, 10:50 UTC2h 20m
2026-07-07 KMM422 MLA → BRU Jul 7, 04:30 UTCJul 7, 07:05 UTC2h 35m
2026-07-06 KMM421 BRU → MLA Jul 6, 18:20 UTCJul 6, 20:45 UTC2h 25m
2026-07-06 KMM420 MLA → BRU Jul 6, 14:30 UTCJul 6, 17:10 UTC2h 40m
2026-07-06 KMM101 - Jul 6, 10:25 UTCJul 6, 13:05 UTC2h 40m
2026-07-06 KMM100A MLA → LHR Jul 6, 05:40 UTCJul 6, 08:55 UTC3h 15m
2026-07-05 KMM491 ZRH → MLA Jul 5, 17:35 UTCJul 5, 19:25 UTC1h 50m
2026-07-05 KMM490 MLA → ZRH Jul 5, 13:40 UTCJul 5, 15:50 UTC2h 10m
2026-07-05 KMM307 - Jul 5, 09:55 UTCJul 5, 11:45 UTC1h 50m
2026-07-05 KMM306 MLA → MUC Jul 5, 05:15 UTCJul 5, 07:30 UTC2h 15m
2026-07-04 KMM103 - Jul 4, 20:00 UTCJul 4, 22:40 UTC2h 40m
2026-07-04 KMM102 MLA → LHR Jul 4, 15:10 UTCJul 4, 18:10 UTC3h 0m
2026-07-04 KMM101 - Jul 4, 10:25 UTCJul 4, 13:00 UTC2h 35m
2026-07-04 KMM100A MLA → LHR Jul 4, 05:15 UTCJul 4, 08:35 UTC3h 20m
2026-07-03 KMM515 VIE → MLA Jul 3, 19:45 UTCJul 3, 21:40 UTC1h 55m
2026-07-03 KMM514 MLA → VIE Jul 3, 16:30 UTCJul 3, 18:25 UTC1h 55m
2026-07-03 KMM625 LIN → MLA Jul 3, 13:50 UTCJul 3, 15:20 UTC1h 30m

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?
Yes. Mode-S 4D21DB is currently airborne.
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.