sensors Mode-S transponder

4D21EA

ICAO 24-bit transponder address · allocated to Malta

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

Hex
4D21EA
Octal
23220752
Decimal
5,054,954
Country
MT
Tail
9H-QAB
Type
B738
No current signal · last broadcast 12h ago
Flights observed
17
Distinct callsigns
10
Country
MT
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S 4D21EA.

Country allocation

The ICAO 24-bit address 4D21EA 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 10 distinct

Callsign Airline Flights Last seen
RYR2664 - 3 2026-04-13
RYR59GQ Ryanair 2 2026-04-13
RYR517L - 2 2026-04-13
RYR2557 - 2 2026-04-13
RYR1DC - 2 2026-04-14
RYR13KA - 2 2026-04-13
RYR8UC - 1 2026-04-13
RYR877 - 1 2026-04-14
RYR6LF - 1 2026-04-12
RYR3LE - 1 2026-04-14

Recent flights last 17

DateFlightRouteTakeoffLandingDuration
2026-04-14 RYR877 - Apr 14, 09:10 UTCApr 14, 10:25 UTC1h 15m
2026-04-14 RYR1DC - Apr 14, 07:10 UTCApr 14, 08:15 UTC1h 5m
2026-04-14 RYR1DC - Apr 14, 06:55 UTCApr 14, 07:10 UTC15m
2026-04-14 RYR3LE - Apr 14, 05:15 UTCApr 14, 05:55 UTC40m
2026-04-13 RYR2557 - Apr 13, 19:45 UTCApr 13, 19:55 UTC10m
2026-04-13 RYR2557 - Apr 13, 18:30 UTCApr 13, 19:55 UTC1h 25m
2026-04-13 RYR517L - Apr 13, 16:15 UTCApr 13, 17:35 UTC1h 20m
2026-04-13 RYR517L - Apr 13, 16:10 UTCApr 13, 17:35 UTC1h 25m
2026-04-13 RYR2664 - Apr 13, 12:20 UTCApr 13, 13:00 UTC40m
2026-04-13 RYR2664 - Apr 13, 11:55 UTCApr 13, 13:00 UTC1h 5m
2026-04-13 RYR2664 - Apr 13, 11:40 UTCApr 13, 12:15 UTC35m
2026-04-13 RYR59GQ TRN → BRI Apr 13, 08:20 UTCApr 13, 08:50 UTC30m
2026-04-13 RYR59GQ TRN → BRI Apr 13, 07:45 UTCApr 13, 08:15 UTC30m
2026-04-13 RYR8UC - Apr 13, 06:00 UTCApr 13, 06:55 UTC55m
2026-04-13 RYR13KA - Apr 13, 04:20 UTCApr 13, 04:55 UTC35m
2026-04-13 RYR13KA - Apr 13, 04:05 UTCApr 13, 04:15 UTC10m
2026-04-12 RYR6LF - Apr 12, 17:45 UTCApr 12, 19:20 UTC1h 35m

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

Mode-S 4D21EA frequently asked

What is Mode-S code 4D21EA?
4D21EA is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-QAB.
Where is Mode-S 4D21EA registered?
Mode-S code 4D21EA is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21EA broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21EA, octal 23220752, decimal 5,054,954.
What flights does 4D21EA operate?
Mode-S 4D21EA has broadcast 10 distinct callsigns, including RYR2664, RYR59GQ, RYR517L, RYR2557, RYR1DC.