Apparatus

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sensors Mode-S transponder

4D21F6

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-CRI · BOEING 737-800

Hex
4D21F6
Octal
23220766
Decimal
5,054,966
Country
MT
Tail
9H-CRI
Type
B738
No current signal · last broadcast Jul 26, 18:40 UTC
Flights observed
653
Distinct callsigns
20
Country
MT
Last broadcast
Jul 26, 18:40 UTC

Last known position

Most recent position reported by Mode-S 4D21F6.

Country allocation

The ICAO 24-bit address 4D21F6 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
AEZ139V - 16 2026-07-21
AEZ31TR - 14 2026-07-23
AEZ318W - 13 2026-07-06
AEZ29JD Aerial Transit Company 13 2026-07-21
AEZ839Y - 12 2026-06-30
AEZ833J - 12 2026-07-21
AEZ569P - 12 2026-07-16
AEZ385Z - 12 2026-06-30
AEZ2616 - 12 2026-07-06
AEZ2347 Aerial Transit Company 12 2026-07-26
AEZ836S - 11 2026-07-20
AEZ7117 - 11 2026-07-08
AEZ60RG - 11 2026-07-08
AEZ413P - 11 2026-07-16
AEZ38TM - 11 2026-07-20
AEZ2361 Aerial Transit Company 11 2026-06-22
AEZ2360 Aerial Transit Company 11 2026-06-22
AEZ835L - 10 2026-07-20
AEZ8094 Aerial Transit Company 10 2026-07-24
AEZ7813 - 10 2026-07-06

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 AEZ2347 FCO → CAG Jul 26, 18:00 UTCJul 26, 18:40 UTC40m
2026-07-26 AEZ40GR CAG → FCO Jul 26, 08:00 UTCJul 26, 08:35 UTC35m
2026-07-25 AEZ69FS - Jul 25, 19:10 UTCJul 25, 20:10 UTC1h 0m
2026-07-25 AEZ75HH - Jul 25, 16:40 UTCJul 25, 17:40 UTC1h 0m
2026-07-25 AEZ8765 LIN → CAG Jul 25, 12:15 UTCJul 25, 13:10 UTC55m
2026-07-25 AEZ41ST CAG → LIN Jul 25, 10:05 UTCJul 25, 11:00 UTC55m
2026-07-25 AEZ8662 CAG → FCO Jul 25, 07:25 UTCJul 25, 08:15 UTC50m
2026-07-25 AEZ94GL CAG → LIN Jul 25, 05:20 UTCJul 25, 06:15 UTC55m
2026-07-24 AEZ2363 LIN → CAG Jul 24, 18:15 UTCJul 24, 19:10 UTC55m
2026-07-24 AEZ14UJ CAG → LIN Jul 24, 15:50 UTCJul 24, 16:55 UTC1h 5m
2026-07-24 AEZ88LL LIN → CAG Jul 24, 13:15 UTCJul 24, 14:05 UTC50m
2026-07-24 AEZ47LG - Jul 24, 10:55 UTCJul 24, 11:55 UTC1h 0m
2026-07-24 AEZ8094 LIN → CAG Jul 24, 08:30 UTCJul 24, 09:20 UTC50m
2026-07-24 AEZ44LG CAG → LIN Jul 24, 06:25 UTCJul 24, 07:25 UTC1h 0m
2026-07-23 AEZ2349 FCO → CAG Jul 23, 20:20 UTCJul 23, 20:50 UTC30m
2026-07-23 AEZ31TR - Jul 23, 07:45 UTCJul 23, 08:10 UTC25m
2026-07-23 AEZ7811 - Jul 23, 05:55 UTCJul 23, 06:15 UTC20m
2026-07-22 AEZ2575 IBZ → FCO Jul 22, 16:55 UTCJul 22, 18:15 UTC1h 20m
2026-07-22 AEZ2574 - Jul 22, 14:05 UTCJul 22, 15:35 UTC1h 30m
2026-07-22 AEZ7810 - Jul 22, 05:15 UTCJul 22, 05:25 UTC10m
2026-07-21 AEZ833J - Jul 21, 17:00 UTCJul 21, 17:45 UTC45m
2026-07-21 AEZ29JD OLB → LIN Jul 21, 14:30 UTCJul 21, 15:25 UTC55m
2026-07-21 AEZ131R FCO → OLB Jul 21, 11:35 UTCJul 21, 12:15 UTC40m
2026-07-21 AEZ7812 - Jul 21, 09:35 UTCJul 21, 10:05 UTC30m
2026-07-21 AEZ139V - Jul 21, 07:45 UTCJul 21, 08:05 UTC20m
2026-07-21 AEZ7810 - Jul 21, 05:00 UTCJul 21, 05:35 UTC35m
2026-07-20 AEZ7341 LIN → OLB Jul 20, 20:35 UTCJul 20, 21:20 UTC45m
2026-07-20 AEZ7340 - Jul 20, 18:40 UTCJul 20, 19:30 UTC50m
2026-07-20 AEZ833J - Jul 20, 16:45 UTCJul 20, 17:35 UTC50m
2026-07-20 AEZ29JD OLB → LIN Jul 20, 14:45 UTCJul 20, 15:35 UTC50m
2026-07-20 AEZ835L - Jul 20, 11:50 UTCJul 20, 12:50 UTC1h 0m
2026-07-20 AEZ38TM - Jul 20, 09:50 UTCJul 20, 10:40 UTC50m
2026-07-20 AEZ836S - Jul 20, 07:45 UTCJul 20, 08:30 UTC45m
2026-07-20 AEZ94GL - Jul 20, 05:25 UTCJul 20, 06:20 UTC55m
2026-07-19 AEZ2363 LIN → CAG Jul 19, 17:50 UTCJul 19, 18:40 UTC50m
2026-07-19 AEZ14UJ - Jul 19, 15:35 UTCJul 19, 16:30 UTC55m
2026-07-19 AEZ88LL LIN → CAG Jul 19, 12:55 UTCJul 19, 13:45 UTC50m
2026-07-19 AEZ47LG - Jul 19, 10:50 UTCJul 19, 11:45 UTC55m
2026-07-19 AEZ8094 LIN → CAG Jul 19, 08:35 UTCJul 19, 09:25 UTC50m
2026-07-19 AEZ44LG CAG → LIN Jul 19, 06:30 UTCJul 19, 07:20 UTC50m
2026-07-18 AEZ11LJ FCO → CAG Jul 18, 16:50 UTCJul 18, 17:30 UTC40m
2026-07-18 AEZ311L OLB → FCO Jul 18, 14:00 UTCJul 18, 14:30 UTC30m
2026-07-18 AEZ835L LIN → OLB Jul 18, 11:45 UTCJul 18, 12:45 UTC1h 0m
2026-07-18 AEZ38TM OLB → LIN Jul 18, 09:20 UTCJul 18, 10:05 UTC45m
2026-07-18 AEZ836S - Jul 18, 07:05 UTCJul 18, 08:05 UTC1h 0m
2026-07-18 AEZ389L - Jul 18, 05:10 UTCJul 18, 05:50 UTC40m
2026-07-17 AEZ7341 LIN → OLB Jul 17, 20:55 UTCJul 17, 21:50 UTC55m
2026-07-17 AEZ7340 - Jul 17, 18:44 UTCJul 17, 19:35 UTC50m
2026-07-17 AEZ833J - Jul 17, 16:49 UTCJul 17, 17:50 UTC1h 0m
2026-07-17 AEZ29JD OLB → LIN Jul 17, 14:35 UTCJul 17, 15:20 UTC45m

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

Mode-S 4D21F6 frequently asked

What is Mode-S code 4D21F6?
4D21F6 is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-CRI.
Where is Mode-S 4D21F6 registered?
Mode-S code 4D21F6 is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21F6 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 18:40 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21F6, octal 23220766, decimal 5,054,966.
What flights does 4D21F6 operate?
Mode-S 4D21F6 has broadcast 20 distinct callsigns, including AEZ139V, AEZ31TR, AEZ318W, AEZ29JD, AEZ839Y.