sensors Mode-S transponder

4D2421

ICAO 24-bit transponder address

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

Hex
4D2421
Octal
23222041
Decimal
5,055,521
Tail
9H-WAL
Type
A21N
No current signal · last broadcast 2h ago
Flights observed
29
Distinct callsigns
20
Country
-
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 4D2421.

Callsign history 20 distinct

Callsign Airline Flights Last seen
WZZ8594 - 1 2026-06-12
WZZ6DX Wizz Air 1 2026-06-12
WZZ64YA Wizz Air 1 2026-06-10
WZZ60QL Wizz Air 1 2026-06-12
WZZ5MD Wizz Air 1 2026-06-10
WZZ58 Wizz Air 1 2026-06-09
WZZ57X Wizz Air 1 2026-06-10
WZZ55KB Wizz Air 1 2026-06-11
WZZ5510 - 1 2026-06-11
WZZ54ZM - 1 2026-06-11
WZZ4SM Wizz Air 1 2026-06-10
WZZ48 Wizz Air 1 2026-06-09
WZZ4782 Wizz Air 1 2026-06-12
WZZ43DZ Wizz Air 1 2026-06-08
WZZ427 Wizz Air 1 2026-06-12
WZZ411 Wizz Air 1 2026-06-09
WZZ406 Wizz Air 1 2026-06-08
WZZ4 - 1 2026-06-13
WZZ39GE - 1 2026-06-13
WZZ386 - 1 2026-06-09

Recent flights last 29

DateFlightRouteTakeoffLandingDuration
2026-06-13 WZZ4 BCN → WAW Jun 13, 07:55 UTCJun 13, 10:35 UTC2h 40m
2026-06-13 WZZ39GE - Jun 13, 04:00 UTCJun 13, 06:30 UTC2h 30m
2026-06-12 WZZ427 TLL → MXP Jun 12, 18:01 UTCJun 12, 20:40 UTC2h 40m
2026-06-12 WZZ8594 - Jun 12, 14:30 UTCJun 12, 16:55 UTC2h 25m
2026-06-12 WZZ60QL DTM → WAW Jun 12, 12:05 UTCJun 12, 13:25 UTC1h 20m
2026-06-12 WZZ4782 CGN → SKP Jun 12, 09:25 UTCJun 12, 11:00 UTC1h 35m
2026-06-12 WZZ6DX SPU → WAW Jun 12, 07:10 UTCJun 12, 08:35 UTC1h 25m
2026-06-12 WZZ1D WAW → SPU Jun 12, 04:35 UTCJun 12, 05:50 UTC1h 15m
2026-06-11 WZZ1319 TGD → WAW Jun 11, 19:20 UTCJun 11, 21:55 UTC2h 35m
2026-06-11 WZZ54ZM WAW → RHO Jun 11, 15:30 UTCJun 11, 18:15 UTC2h 45m
2026-06-11 WZZ3357 TLL → WAW Jun 11, 12:45 UTCJun 11, 14:10 UTC1h 25m
2026-06-11 WZZ55KB WAW → TLL Jun 11, 10:50 UTCJun 11, 11:55 UTC1h 5m
2026-06-11 WZZ1344 - Jun 11, 09:20 UTCJun 11, 09:50 UTC30m
2026-06-11 WZZ5510 - Jun 11, 06:30 UTCJun 11, 07:55 UTC1h 25m
2026-06-11 WZZ30WF KTW → VAR Jun 11, 03:55 UTCJun 11, 05:30 UTC1h 35m
2026-06-10 WZZ1641 GDN → EIN Jun 10, 20:30 UTCJun 10, 23:35 UTC3h 5m
2026-06-10 WZZ17ZC KTW → OPO Jun 10, 15:40 UTCJun 10, 19:05 UTC3h 25m
2026-06-10 WZZ5MD EIN → KTW Jun 10, 13:20 UTCJun 10, 14:40 UTC1h 20m
2026-06-10 WZZ4SM OTP → PRG Jun 10, 10:50 UTCJun 10, 12:25 UTC1h 35m
2026-06-10 WZZ64YA LTN → KTW Jun 10, 08:00 UTCJun 10, 09:50 UTC1h 50m
2026-06-10 WZZ57X KTW → LTN Jun 10, 04:20 UTCJun 10, 06:30 UTC2h 10m
2026-06-09 WZZ411 PRN → DTM Jun 9, 17:40 UTCJun 9, 18:10 UTC30m
2026-06-09 WZZ386 - Jun 9, 15:15 UTCJun 9, 15:50 UTC35m
2026-06-09 WZZ1074 AGP → KTW Jun 9, 13:00 UTCJun 9, 14:20 UTC1h 20m
2026-06-09 WZZ48 KRK → OTP Jun 9, 08:30 UTCJun 9, 11:30 UTC3h 0m
2026-06-09 WZZ58 WAW → TLV Jun 9, 03:50 UTCJun 9, 07:15 UTC3h 25m
2026-06-08 WZZ1714 - Jun 8, 21:00 UTCJun 8, 23:10 UTC2h 10m
2026-06-08 WZZ43DZ WRO → CTA Jun 8, 17:55 UTCJun 8, 19:50 UTC1h 55m
2026-06-08 WZZ406 DTM → PRN Jun 8, 16:30 UTCJun 8, 17:00 UTC30m

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

Mode-S 4D2421 frequently asked

What is Mode-S code 4D2421?
4D2421 is an ICAO 24-bit transponder address. Assigned to 9H-WAL.
Is 4D2421 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D2421, octal 23222041, decimal 5,055,521.
What flights does 4D2421 operate?
Mode-S 4D2421 has broadcast 20 distinct callsigns, including WZZ8594, WZZ6DX, WZZ64YA, WZZ60QL, WZZ5MD.