Apparatus

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sensors Mode-S transponder

4D21DC

ICAO 24-bit transponder address · allocated to Malta

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

Hex
4D21DC
Octal
23220734
Decimal
5,054,940
Country
MT
Tail
9H-NEC
Type
A20N
Broadcasting now · callsign KMM117 · 37,000 ft
Flights observed
408
Distinct callsigns
20
Country
MT
Last broadcast
2h ago

Current position

4D21DC is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4D21DC 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
KMM394 - 20 2026-07-03
KMM395 - 19 2026-07-03
KMM420 - 17 2026-07-07
KMM103 - 16 2026-06-28
KMM102 - 16 2026-06-28
KMM421 - 15 2026-07-07
KMM101 - 15 2026-06-27
KMM100A - 15 2026-06-27
KMM514 - 13 2026-07-07
KMM615 - 12 2026-06-25
KMM614 - 12 2026-06-25
KMM613 - 12 2026-07-05
KMM612 - 12 2026-07-05
KMM515 - 12 2026-07-07
KMM467 - 12 2026-06-27
KMM466 - 12 2026-06-27
KMM625 - 11 2026-06-25
KMM624 - 11 2026-06-25
KMM116 - 9 2026-07-14
KMM309 - 8 2026-07-04

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 KMM116 MLA → LGW Jul 14, 06:35 UTCJul 14, 09:40 UTC3h 5m
2026-07-08 KMM353 DUS → MLA Jul 8, 08:45 UTCJul 8, 11:00 UTC2h 15m
2026-07-08 KMM352 MLA → DUS Jul 8, 04:10 UTCJul 8, 06:50 UTC2h 40m
2026-07-07 KMM421 BRU → MLA Jul 7, 18:15 UTCJul 7, 20:40 UTC2h 25m
2026-07-07 KMM420 - Jul 7, 16:20 UTCJul 7, 16:55 UTC35m
2026-07-07 KMM420 - Jul 7, 14:20 UTCJul 7, 16:15 UTC1h 55m
2026-07-07 KMM515 - Jul 7, 10:45 UTCJul 7, 12:45 UTC2h 0m
2026-07-07 KMM514 MLA → VIE Jul 7, 07:25 UTCJul 7, 09:30 UTC2h 5m
2026-07-06 KMM587 - Jul 6, 20:25 UTCJul 6, 22:35 UTC2h 10m
2026-07-06 KMM586 MLA → MAD Jul 6, 16:20 UTCJul 6, 18:50 UTC2h 30m
2026-07-06 KMM515 VIE → MLA Jul 6, 11:00 UTCJul 6, 12:55 UTC1h 55m
2026-07-06 KMM514 MLA → VIE Jul 6, 07:25 UTCJul 6, 09:30 UTC2h 5m
2026-07-05 KMM627 LIN → MLA Jul 5, 18:55 UTCJul 5, 20:30 UTC1h 35m
2026-07-05 KMM626 MLA → LIN Jul 5, 16:10 UTCJul 5, 17:55 UTC1h 45m
2026-07-05 KMM617 FCO → MLA Jul 5, 14:10 UTCJul 5, 15:15 UTC1h 5m
2026-07-05 KMM616 - Jul 5, 11:20 UTCJul 5, 12:25 UTC1h 5m
2026-07-05 KMM613 - Jul 5, 08:40 UTCJul 5, 09:40 UTC1h 0m
2026-07-05 KMM612 - Jul 5, 05:10 UTCJul 5, 06:20 UTC1h 10m
2026-07-04 KMM643 - Jul 4, 20:15 UTCJul 4, 20:40 UTC25m
2026-07-04 KMM642 - Jul 4, 18:35 UTCJul 4, 19:00 UTC25m
2026-07-04 KMM309 - Jul 4, 15:25 UTCJul 4, 17:20 UTC1h 55m
2026-07-04 KMM308 - Jul 4, 11:55 UTCJul 4, 14:00 UTC2h 5m
2026-07-04 KMM587 - Jul 4, 08:20 UTCJul 4, 10:30 UTC2h 10m
2026-07-04 KMM586 - Jul 4, 04:15 UTCJul 4, 06:25 UTC2h 10m
2026-07-03 KMM107 - Jul 3, 18:25 UTCJul 3, 21:05 UTC2h 40m
2026-07-03 KMM106 MLA → LHR Jul 3, 14:15 UTCJul 3, 17:20 UTC3h 5m
2026-07-03 KMM395 AMS → MLA Jul 3, 10:30 UTCJul 3, 13:05 UTC2h 35m
2026-07-03 KMM394 MLA → AMS Jul 3, 05:55 UTCJul 3, 08:50 UTC2h 55m
2026-07-02 KMM3119 - Jul 2, 17:35 UTCJul 2, 20:20 UTC2h 45m
2026-07-02 KMM3118 MLA → LGW Jul 2, 12:20 UTCJul 2, 15:20 UTC3h 0m
2026-07-02 KMM785 - Jul 2, 08:00 UTCJul 2, 10:05 UTC2h 5m
2026-07-02 KMM784 - Jul 2, 04:25 UTCJul 2, 06:15 UTC1h 50m
2026-07-01 KMM421 - Jul 1, 18:20 UTCJul 1, 20:40 UTC2h 20m
2026-07-01 KMM420 MLA → BRU Jul 1, 14:35 UTCJul 1, 17:10 UTC2h 35m
2026-07-01 KMM395 - Jul 1, 10:10 UTCJul 1, 13:00 UTC2h 50m
2026-07-01 KMM394 - Jul 1, 05:40 UTCJul 1, 08:40 UTC3h 0m
2026-06-30 KMM309 MUC → MLA Jun 30, 15:45 UTCJun 30, 17:40 UTC1h 55m
2026-06-30 KMM308 MLA → MUC Jun 30, 12:30 UTCJun 30, 14:30 UTC2h 0m
2026-06-30 KMM479 - Jun 30, 08:15 UTCJun 30, 10:40 UTC2h 25m
2026-06-30 KMM478 MLA → CDG Jun 30, 04:10 UTCJun 30, 06:40 UTC2h 30m
2026-06-29 KMM397 - Jun 29, 17:49 UTCJun 29, 20:24 UTC2h 35m
2026-06-29 KMM396 MLA → AMS Jun 29, 13:19 UTCJun 29, 16:00 UTC2h 40m
2026-06-29 KMM785 - Jun 29, 07:44 UTCJun 29, 09:44 UTC2h 0m
2026-06-29 KMM784 - Jun 29, 04:09 UTCJun 29, 06:14 UTC2h 5m
2026-06-28 KMM103 - Jun 28, 20:25 UTCJun 28, 23:25 UTC3h 0m
2026-06-28 KMM102 MLA → LHR Jun 28, 14:59 UTCJun 28, 18:00 UTC3h 0m
2026-06-28 KMM395 - Jun 28, 10:15 UTCJun 28, 12:55 UTC2h 40m
2026-06-28 KMM394 - Jun 28, 05:34 UTCJun 28, 08:29 UTC2h 55m
2026-06-27 KMM467 ORY → MLA Jun 27, 19:39 UTCJun 27, 22:04 UTC2h 25m
2026-06-27 KMM466 MLA → ORY Jun 27, 15:34 UTCJun 27, 17:59 UTC2h 25m

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

Mode-S 4D21DC frequently asked

What is Mode-S code 4D21DC?
4D21DC is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-NEC.
Where is Mode-S 4D21DC registered?
Mode-S code 4D21DC is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21DC broadcasting right now?
Yes. Mode-S 4D21DC is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21DC, octal 23220734, decimal 5,054,940.
What flights does 4D21DC operate?
Mode-S 4D21DC has broadcast 20 distinct callsigns, including KMM394, KMM395, KMM420, KMM103, KMM102.