sensors Mode-S transponder

4D2021

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-WNT · AIRBUS A-321neo

Hex
4D2021
Octal
23220041
Decimal
5,054,497
Country
MT
Tail
9H-WNT
Type
A21N
Broadcasting now · callsign WZZ3LA · 21,225 ft
Flights observed
17
Distinct callsigns
11
Country
MT
Last broadcast
18h ago

Current position

4D2021 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4D2021 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 11 distinct

Callsign Airline Flights Last seen
WZZ654 - 3 2026-04-13
WZZ5006 - 3 2026-04-13
WZZ4005 - 2 2026-04-13
WZZ3050 - 2 2026-04-13
WZZ6260 - 1 2026-04-14
WZZ5SD - 1 2026-04-13
WZZ5965 - 1 2026-04-14
WZZ306 Wizz Air 1 2026-04-13
WZZ299 - 1 2026-04-12
WZZ227 - 1 2026-04-14
WZZ1919 - 1 2026-04-12

Recent flights last 17

DateFlightRouteTakeoffLandingDuration
2026-04-14 WZZ227 - Apr 14, 10:05 UTCApr 14, 11:05 UTC1h 0m
2026-04-14 WZZ6260 - Apr 14, 08:05 UTCApr 14, 09:05 UTC1h 0m
2026-04-14 WZZ5965 - Apr 14, 05:15 UTCApr 14, 06:20 UTC1h 5m
2026-04-13 WZZ3050 - Apr 13, 19:50 UTCApr 13, 20:55 UTC1h 5m
2026-04-13 WZZ3050 - Apr 13, 19:25 UTCApr 13, 20:10 UTC45m
2026-04-13 WZZ5SD - Apr 13, 16:30 UTCApr 13, 18:15 UTC1h 45m
2026-04-13 WZZ306 GDN → SPU Apr 13, 13:35 UTCApr 13, 14:55 UTC1h 20m
2026-04-13 WZZ4005 - Apr 13, 11:55 UTCApr 13, 12:20 UTC25m
2026-04-13 WZZ4005 - Apr 13, 10:25 UTCApr 13, 12:15 UTC1h 50m
2026-04-13 WZZ654 - Apr 13, 08:20 UTCApr 13, 09:00 UTC40m
2026-04-13 WZZ654 - Apr 13, 07:55 UTCApr 13, 09:00 UTC1h 5m
2026-04-13 WZZ654 - Apr 13, 06:50 UTCApr 13, 08:15 UTC1h 25m
2026-04-13 WZZ5006 - Apr 13, 04:20 UTCApr 13, 05:35 UTC1h 15m
2026-04-13 WZZ5006 - Apr 13, 03:55 UTCApr 13, 05:35 UTC1h 40m
2026-04-13 WZZ5006 - Apr 13, 03:30 UTCApr 13, 04:15 UTC45m
2026-04-12 WZZ299 - Apr 12, 19:45 UTCApr 12, 20:15 UTC30m
2026-04-12 WZZ1919 - Apr 12, 17:15 UTCApr 12, 17:55 UTC40m

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

Mode-S 4D2021 frequently asked

What is Mode-S code 4D2021?
4D2021 is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-WNT.
Where is Mode-S 4D2021 registered?
Mode-S code 4D2021 is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D2021 broadcasting right now?
Yes. Mode-S 4D2021 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D2021, octal 23220041, decimal 5,054,497.
What flights does 4D2021 operate?
Mode-S 4D2021 has broadcast 11 distinct callsigns, including WZZ654, WZZ5006, WZZ4005, WZZ3050, WZZ6260.