Apparatus

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sensors Mode-S transponder

4D21B5

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-GKM · CESSNA 560XL Citation XLS

Hex
4D21B5
Octal
23220665
Decimal
5,054,901
Country
MT
Tail
9H-GKM
Type
C56X
Broadcasting now · callsign VCJ50M · 40,000 ft
Flights observed
83
Distinct callsigns
1
Country
MT
Last broadcast
19h ago

Current position

4D21B5 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4D21B5 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 1 distinct

Callsign Airline Flights Last seen
VCJ50M - 83 2026-07-13

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 VCJ50M - Jul 13, 19:10 UTCJul 13, 21:30 UTC2h 20m
2026-07-13 VCJ50M - Jul 13, 06:15 UTCJul 13, 08:35 UTC2h 20m
2026-07-10 VCJ50M - Jul 10, 16:40 UTCJul 10, 18:35 UTC1h 55m
2026-07-09 VCJ50M - Jul 9, 10:00 UTCJul 9, 10:40 UTC40m
2026-07-09 VCJ50M VIE → FRA Jul 9, 07:05 UTCJul 9, 08:20 UTC1h 15m
2026-07-06 VCJ50M - Jul 6, 18:20 UTCJul 6, 20:20 UTC2h 0m
2026-07-06 VCJ50M ZRH → ISL Jul 6, 15:05 UTCJul 6, 17:35 UTC2h 30m
2026-07-06 VCJ50M SZG → ZRH Jul 6, 12:10 UTCJul 6, 12:55 UTC45m
2026-07-04 VCJ50M LBG → SZG Jul 4, 15:00 UTCJul 4, 16:15 UTC1h 15m
2026-06-28 VCJ50M - Jun 28, 07:05 UTCJun 28, 07:54 UTC50m
2026-06-28 VCJ50M BTS → FRA Jun 28, 05:24 UTCJun 28, 06:30 UTC1h 5m
2026-06-27 VCJ50M - Jun 27, 12:29 UTCJun 27, 13:15 UTC45m
2026-06-27 VCJ50M - Jun 27, 11:09 UTCJun 27, 11:55 UTC45m
2026-06-27 VCJ50M - Jun 27, 09:19 UTCJun 27, 09:55 UTC35m
2026-06-25 VCJ50M ZRH → SZG Jun 25, 09:45 UTCJun 25, 10:20 UTC35m
2026-06-24 VCJ50M - Jun 24, 18:09 UTCJun 24, 18:50 UTC40m
2026-06-24 VCJ50M - Jun 24, 08:14 UTCJun 24, 08:49 UTC35m
2026-06-24 VCJ50M BTS → ZRH Jun 24, 06:04 UTCJun 24, 07:10 UTC1h 5m
2026-06-23 VCJ50M - Jun 23, 18:20 UTCJun 23, 19:00 UTC40m
2026-06-22 VCJ50M - Jun 22, 16:29 UTCJun 22, 17:00 UTC30m
2026-06-22 VCJ50M - Jun 22, 13:54 UTCJun 22, 14:29 UTC35m
2026-06-18 VCJ50M - Jun 18, 16:25 UTCJun 18, 17:05 UTC40m
2026-06-18 VCJ50M - Jun 18, 14:40 UTCJun 18, 15:45 UTC1h 5m
2026-06-15 VCJ50M ZRH → AMS Jun 15, 06:15 UTCJun 15, 07:35 UTC1h 20m
2026-06-15 VCJ50M - Jun 15, 04:04 UTCJun 15, 04:45 UTC40m
2026-06-12 VCJ50M ZRH → SZG Jun 12, 18:35 UTCJun 12, 19:10 UTC35m
2026-06-12 VCJ50M - Jun 12, 16:00 UTCJun 12, 17:40 UTC1h 40m
2026-06-12 VCJ50M - Jun 12, 14:30 UTCJun 12, 15:25 UTC55m
2026-06-12 VCJ50M - Jun 12, 12:05 UTCJun 12, 13:10 UTC1h 5m
2026-06-08 VCJ50M VIE → SZG Jun 8, 15:45 UTCJun 8, 18:10 UTC2h 25m
2026-06-08 VCJ50M ZRH → VIE Jun 8, 05:50 UTCJun 8, 06:45 UTC55m
2026-06-07 VCJ50M SZG → ZRH Jun 7, 16:55 UTCJun 7, 17:35 UTC40m
2026-06-02 VCJ50M ZRH → SZG Jun 2, 19:30 UTCJun 2, 20:05 UTC35m
2026-06-02 VCJ50M - Jun 2, 17:30 UTCJun 2, 18:50 UTC1h 20m
2026-06-01 VCJ50M ZRH → FAB Jun 1, 06:15 UTCJun 1, 07:40 UTC1h 25m
2026-05-31 VCJ50M - May 31, 16:05 UTCMay 31, 18:00 UTC1h 55m
2026-05-31 VCJ50M - May 31, 12:20 UTCMay 31, 14:10 UTC1h 50m
2026-05-30 VCJ50M - May 30, 15:20 UTCMay 30, 15:55 UTC35m
2026-05-29 VCJ50M ZRH → SZG May 29, 16:30 UTCMay 29, 17:05 UTC35m
2026-05-29 VCJ50M - May 29, 15:00 UTCMay 29, 15:45 UTC45m
2026-05-29 VCJ50M - May 29, 12:35 UTCMay 29, 13:30 UTC55m
2026-05-27 VCJ50M - May 27, 18:45 UTCMay 27, 19:15 UTC30m
2026-05-27 VCJ50M - May 27, 17:40 UTCMay 27, 18:20 UTC40m
2026-05-27 VCJ50M ZRH → SZG May 27, 07:55 UTCMay 27, 08:35 UTC40m
2026-05-26 VCJ50M - May 26, 14:20 UTCMay 26, 14:55 UTC35m
2026-05-26 VCJ50M BTS → FRA May 26, 11:30 UTCMay 26, 12:45 UTC1h 15m
2026-05-26 VCJ50M ZRH → BTS May 26, 04:20 UTCMay 26, 05:25 UTC1h 5m
2026-05-25 VCJ50M - May 25, 14:55 UTCMay 25, 15:30 UTC35m
2026-05-24 VCJ50M MAD → SZG May 24, 11:25 UTCMay 24, 13:40 UTC2h 15m
2026-05-24 VCJ50M - May 24, 06:15 UTCMay 24, 08:30 UTC2h 15m

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

Mode-S 4D21B5 frequently asked

What is Mode-S code 4D21B5?
4D21B5 is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-GKM.
Where is Mode-S 4D21B5 registered?
Mode-S code 4D21B5 is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21B5 broadcasting right now?
Yes. Mode-S 4D21B5 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21B5, octal 23220665, decimal 5,054,901.
What flights does 4D21B5 operate?
Mode-S 4D21B5 has broadcast 1 distinct callsign, including VCJ50M.