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 KMM586 · 38,000 ft
Flights observed
232
Distinct callsigns
20
Country
MT
Last broadcast
6h 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 - 15 2026-05-29
KMM306 - 15 2026-05-29
KMM491 - 11 2026-05-26
KMM490 - 11 2026-05-26
KMM613 - 8 2026-05-25
KMM612 - 8 2026-05-25
KMM421 - 8 2026-05-13
KMM420 - 8 2026-05-13
KMM100A - 8 2026-05-11
KMM514 - 7 2026-05-27
KMM103 - 7 2026-05-29
KMM102 - 7 2026-05-29
KMM101 - 7 2026-05-11
KMM625 - 6 2026-05-25
KMM624 - 6 2026-05-25
KMM615 - 6 2026-05-25
KMM614 - 6 2026-05-25
KMM515 - 6 2026-05-27
KMM454 - 6 2026-05-28
KMM308 - 6 2026-05-28

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 KMM103 - May 29, 19:55 UTCMay 29, 22:35 UTC2h 40m
2026-05-29 KMM102 MLA → LHR May 29, 15:15 UTCMay 29, 18:15 UTC3h 1m
2026-05-29 KMM307 MUC → MLA May 29, 09:30 UTCMay 29, 11:25 UTC1h 55m
2026-05-29 KMM306 MLA → MUC May 29, 05:25 UTCMay 29, 07:25 UTC2h 0m
2026-05-28 KMM455 LYS → MLA May 28, 22:10 UTCMay 29, 00:00 UTC1h 50m
2026-05-28 KMM454 MLA → LYS May 28, 19:00 UTCMay 28, 20:55 UTC1h 55m
2026-05-28 KMM309 - May 28, 15:40 UTCMay 28, 17:30 UTC1h 50m
2026-05-28 KMM308 MLA → MUC May 28, 12:25 UTCMay 28, 14:25 UTC2h 0m
2026-05-28 KMM479 - May 28, 08:20 UTCMay 28, 10:50 UTC2h 30m
2026-05-28 KMM478A MLA → CDG May 28, 04:30 UTCMay 28, 07:05 UTC2h 35m
2026-05-27 KMM467 ORY → MLA May 27, 18:55 UTCMay 27, 21:15 UTC2h 20m
2026-05-27 KMM466 MLA → ORY May 27, 15:25 UTCMay 27, 17:55 UTC2h 30m
2026-05-27 KMM515 VIE → MLA May 27, 10:35 UTCMay 27, 12:25 UTC1h 50m
2026-05-27 KMM514 MLA → VIE May 27, 07:30 UTCMay 27, 09:25 UTC1h 55m
2026-05-26 KMM491 ZRH → MLA May 26, 15:54 UTCMay 26, 17:55 UTC2h 0m
2026-05-26 KMM490 MLA → ZRH May 26, 12:45 UTCMay 26, 14:40 UTC1h 55m
2026-05-26 KMM307 MUC → MLA May 26, 09:19 UTCMay 26, 11:15 UTC1h 55m
2026-05-26 KMM306 MLA → MUC May 26, 05:25 UTCMay 26, 07:24 UTC2h 0m
2026-05-25 KMM615 - May 25, 19:25 UTCMay 25, 20:30 UTC1h 5m
2026-05-25 KMM614 - May 25, 16:40 UTCMay 25, 17:50 UTC1h 10m
2026-05-25 KMM625 - May 25, 14:00 UTCMay 25, 15:35 UTC1h 35m
2026-05-25 KMM624 MLA → LIN May 25, 11:00 UTCMay 25, 12:35 UTC1h 35m
2026-05-25 KMM613 - May 25, 08:15 UTCMay 25, 09:20 UTC1h 5m
2026-05-25 KMM612 - May 25, 05:15 UTCMay 25, 06:25 UTC1h 10m
2026-05-24 KMM627 - May 24, 18:50 UTCMay 24, 20:25 UTC1h 35m
2026-05-24 KMM626 MLA → LIN May 24, 16:00 UTCMay 24, 17:35 UTC1h 35m
2026-05-24 KMM617 FCO → MLA May 24, 13:55 UTCMay 24, 15:00 UTC1h 5m
2026-05-24 KMM616 - May 24, 11:10 UTCMay 24, 12:25 UTC1h 15m
2026-05-24 KMM613 - May 24, 08:20 UTCMay 24, 09:20 UTC1h 0m
2026-05-24 KMM612 - May 24, 05:05 UTCMay 24, 06:15 UTC1h 10m
2026-05-23 KMM615 FCO → MLA May 23, 19:10 UTCMay 23, 20:10 UTC1h 0m
2026-05-23 KMM614 MLA → FCO May 23, 16:35 UTCMay 23, 17:45 UTC1h 10m
2026-05-23 KMM625 - May 23, 13:55 UTCMay 23, 15:25 UTC1h 30m
2026-05-23 KMM624 MLA → LIN May 23, 11:00 UTCMay 23, 12:45 UTC1h 45m
2026-05-23 KMM613 - May 23, 08:30 UTCMay 23, 09:25 UTC55m
2026-05-23 KMM612 - May 23, 05:15 UTCMay 23, 06:30 UTC1h 15m
2026-05-22 KMM615 FCO → MLA May 22, 19:50 UTCMay 22, 20:50 UTC1h 0m
2026-05-22 KMM614 - May 22, 16:40 UTCMay 22, 17:55 UTC1h 15m
2026-05-22 KMM625 - May 22, 13:50 UTCMay 22, 15:20 UTC1h 30m
2026-05-22 KMM624 MLA → LIN May 22, 10:50 UTCMay 22, 12:40 UTC1h 50m
2026-05-22 KMM613 - May 22, 08:15 UTCMay 22, 09:20 UTC1h 5m
2026-05-22 KMM612 MLA → FCO May 22, 05:15 UTCMay 22, 06:20 UTC1h 5m
2026-05-21 KMM455 LYS → MLA May 21, 23:25 UTCMay 22, 01:15 UTC1h 50m
2026-05-21 KMM454 MLA → LYS May 21, 20:30 UTCMay 21, 22:30 UTC2h 0m
2026-05-21 KMM309 - May 21, 17:30 UTCMay 21, 19:15 UTC1h 45m
2026-05-21 KMM308A MLA → MUC May 21, 14:10 UTCMay 21, 16:25 UTC2h 15m
2026-05-21 KMM308 MLA → MLA May 21, 12:10 UTCMay 21, 12:45 UTC35m
2026-05-21 KMM479 - May 21, 08:45 UTCMay 21, 10:55 UTC2h 10m
2026-05-21 KMM478A MLA → CDG May 21, 04:25 UTCMay 21, 07:05 UTC2h 40m
2026-05-20 KMM377 BER → MLA May 20, 19:10 UTCMay 20, 21:30 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-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, KMM613.