Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

4D2251

ICAO 24-bit transponder address · allocated to Malta

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

Hex
4D2251
Octal
23221121
Decimal
5,055,057
Country
MT
Tail
9H-QCK
Type
B738
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
654
Distinct callsigns
20
Country
MT
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S 4D2251.

Country allocation

The ICAO 24-bit address 4D2251 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
RYR47YB - 6 2026-07-02
RYR2FL - 6 2026-07-02
RYR6QT - 4 2026-07-13
RYR6BY - 4 2026-07-13
RYR49EJ Ryanair 4 2026-04-16
RYR95LW Ryanair 3 2026-06-06
RYR7QP Ryanair 3 2026-07-15
RYR7LX - 3 2026-07-03
RYR67KN - 3 2026-07-03
RYR5ZK - 3 2026-04-14
RYR5WW Ryanair 3 2026-05-13
RYR4BW Ryanair 3 2026-07-15
RYR2RW - 3 2026-07-03
RYR22KC Ryanair 3 2026-06-08
RYR1QD Ryanair 3 2026-06-08
RYR1LC Ryanair 3 2026-05-13
RYR19EW - 3 2026-07-03
RYR9QX Ryanair 2 2026-06-03
RYR9F - 2 2026-07-08
RYR94MC Ryanair 2 2026-06-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RYR97CB OPO → FKB Jul 26, 19:35 UTCJul 26, 21:45 UTC2h 10m
2026-07-26 RYR5482 MAD → OPO Jul 26, 17:40 UTCJul 26, 18:25 UTC45m
2026-07-26 RYR39RJ OPO → MAD Jul 26, 14:05 UTCJul 26, 15:00 UTC55m
2026-07-26 RYR427G AGP → OPO Jul 26, 12:20 UTCJul 26, 13:20 UTC1h 0m
2026-07-26 RYR2YA DUB → PRG Jul 26, 08:55 UTCJul 26, 11:05 UTC2h 10m
2026-07-26 RYR4UU AGA → FEZ Jul 26, 04:20 UTCJul 26, 07:00 UTC2h 41m
2026-07-25 RYR2NL GLA → WRO Jul 25, 23:20 UTCJul 26, 00:00 UTC40m
2026-07-25 RYR2PR FAO → LUX Jul 25, 21:20 UTCJul 25, 22:15 UTC55m
2026-07-25 RYR7KQ WMI → AGP Jul 25, 17:40 UTCJul 25, 20:15 UTC2h 35m
2026-07-25 RYR3JR - Jul 25, 13:00 UTCJul 25, 14:50 UTC1h 50m
2026-07-25 RYR354L BRE → AGP Jul 25, 08:40 UTCJul 25, 11:40 UTC3h 0m
2026-07-25 RYR9929 AGP → BRE Jul 25, 05:00 UTCJul 25, 07:40 UTC2h 40m
2026-07-24 RYR4SZ KRK → CPH Jul 24, 22:00 UTCJul 24, 22:45 UTC45m
2026-07-24 RYR4RL - Jul 24, 20:05 UTCJul 24, 21:10 UTC1h 5m
2026-07-24 RYR66KJ - Jul 24, 16:15 UTCJul 24, 18:35 UTC2h 20m
2026-07-24 RYR3LT - Jul 24, 13:20 UTCJul 24, 15:15 UTC1h 55m
2026-07-24 RYR1XQ AHO → ORK Jul 24, 08:45 UTCJul 24, 11:45 UTC3h 0m
2026-07-24 RYR4726 WRO → SZY Jul 24, 04:55 UTCJul 24, 08:00 UTC3h 5m
2026-07-23 RYR32FQ - Jul 23, 20:25 UTCJul 23, 23:20 UTC2h 55m
2026-07-23 RYR40KU - Jul 23, 16:55 UTCJul 23, 19:45 UTC2h 50m
2026-07-23 RYR1JN ALC → PIK Jul 23, 13:40 UTCJul 23, 15:05 UTC1h 25m
2026-07-23 RYR209J AGP → MAH Jul 23, 11:35 UTCJul 23, 12:45 UTC1h 10m
2026-07-23 RYR9RL - Jul 23, 08:05 UTCJul 23, 10:15 UTC2h 10m
2026-07-23 RYR618X - Jul 23, 05:05 UTCJul 23, 07:15 UTC2h 10m
2026-07-22 RYR4461 FEZ → AGP Jul 22, 22:55 UTCJul 22, 23:30 UTC35m
2026-07-22 RYR81NH AGP → FEZ Jul 22, 21:25 UTCJul 22, 21:50 UTC25m
2026-07-22 RYR64GA MRS → OTP Jul 22, 17:55 UTCJul 22, 20:15 UTC2h 20m
2026-07-22 RYR9VP VIE → MAN Jul 22, 14:35 UTCJul 22, 16:55 UTC2h 20m
2026-07-22 RYR3NN - Jul 22, 11:40 UTCJul 22, 13:20 UTC1h 40m
2026-07-22 RYR86EK AGP → IBZ Jul 22, 04:35 UTCJul 22, 05:25 UTC50m
2026-07-21 RYR31BA WRO → AGP Jul 21, 20:10 UTCJul 21, 23:20 UTC3h 10m
2026-07-21 RYR29EN AGP → WRO Jul 21, 16:15 UTCJul 21, 19:15 UTC3h 0m
2026-07-21 RYR33PK KRK → AGP Jul 21, 12:55 UTCJul 21, 14:35 UTC1h 40m
2026-07-21 RYR33PK KRK → AGP Jul 21, 11:05 UTCJul 21, 12:50 UTC1h 45m
2026-07-21 RYR17MN - Jul 21, 06:40 UTCJul 21, 09:45 UTC3h 5m
2026-07-20 RYR1TQ AGA → MAD Jul 20, 21:10 UTCJul 20, 23:40 UTC2h 30m
2026-07-20 RYR96GG AGP → DUB Jul 20, 17:45 UTCJul 20, 20:20 UTC2h 35m
2026-07-20 RYR31DM - Jul 20, 15:30 UTCJul 20, 16:30 UTC1h 0m
2026-07-20 RYR86EK - Jul 20, 12:55 UTCJul 20, 13:55 UTC1h 0m
2026-07-20 RYR3NN - Jul 20, 09:15 UTCJul 20, 11:00 UTC1h 45m
2026-07-20 RYR8LD - Jul 20, 06:20 UTCJul 20, 07:50 UTC1h 30m
2026-07-19 RYR2NL GLA → WRO Jul 19, 21:10 UTCJul 19, 22:10 UTC1h 0m
2026-07-19 RYR2PR FAO → LUX Jul 19, 19:15 UTCJul 19, 20:00 UTC45m
2026-07-19 RYR9YC BHX → AGP Jul 19, 15:50 UTCJul 19, 18:15 UTC2h 25m
2026-07-19 RYR3MP - Jul 19, 12:30 UTCJul 19, 14:55 UTC2h 25m
2026-07-19 RYR7MN - Jul 19, 07:50 UTCJul 19, 10:55 UTC3h 5m
2026-07-19 RYR85QL AGP → LBC Jul 19, 04:00 UTCJul 19, 06:50 UTC2h 50m
2026-07-18 RYR66KJ - Jul 18, 20:20 UTCJul 18, 22:40 UTC2h 20m
2026-07-18 RYR3LT - Jul 18, 17:25 UTCJul 18, 19:25 UTC2h 0m
2026-07-18 RYR6796 - Jul 18, 14:50 UTCJul 18, 16:15 UTC1h 25m

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

Mode-S 4D2251 frequently asked

What is Mode-S code 4D2251?
4D2251 is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-QCK.
Where is Mode-S 4D2251 registered?
Mode-S code 4D2251 is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D2251 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D2251, octal 23221121, decimal 5,055,057.
What flights does 4D2251 operate?
Mode-S 4D2251 has broadcast 20 distinct callsigns, including RYR47YB, RYR2FL, RYR6QT, RYR6BY, RYR49EJ.