Apparatus

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sensors Mode-S transponder

4D21E9

ICAO 24-bit transponder address · allocated to Malta

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

Hex
4D21E9
Octal
23220751
Decimal
5,054,953
Country
MT
Tail
9H-QAA
Type
B738
No current signal · last broadcast 1h ago
Flights observed
614
Distinct callsigns
20
Country
MT
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S 4D21E9.

Country allocation

The ICAO 24-bit address 4D21E9 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
RYR738U Ryanair 4 2026-05-27
RYR6FR Ryanair 4 2026-05-27
RYR2BD - 4 2026-06-25
RYR2A Ryanair 4 2026-06-25
RYR1237 Ryanair 4 2026-06-25
RYR11EX - 4 2026-06-25
RYR9JQ Ryanair 3 2026-06-06
RYR85AX Ryanair 3 2026-05-22
RYR80PC Ryanair 3 2026-05-24
RYR62BC Ryanair 3 2026-05-22
RYR5YX - 3 2026-04-13
RYR5SF - 3 2026-06-25
RYR5914 Ryanair 3 2026-05-24
RYR4W Ryanair 3 2026-04-14
RYR4RX - 3 2026-06-25
RYR354V Ryanair 3 2026-06-06
RYR348J Ryanair 3 2026-05-05
RYR97SR Ryanair 2 2026-05-21
RYR96RB Ryanair 2 2026-05-26
RYR91QQ - 2 2026-06-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-15 RYR8CV - Jul 15, 07:45 UTCJul 15, 08:15 UTC30m
2026-07-15 RYR8RB - Jul 15, 05:55 UTCJul 15, 06:35 UTC40m
2026-07-15 RYR292Q PSA → CAG Jul 15, 04:20 UTCJul 15, 05:10 UTC50m
2026-07-14 RYR1LB - Jul 14, 20:30 UTCJul 14, 21:45 UTC1h 15m
2026-07-14 RYR66WT - Jul 14, 18:20 UTCJul 14, 19:45 UTC1h 25m
2026-07-14 RYR636Q - Jul 14, 15:45 UTCJul 14, 17:35 UTC1h 50m
2026-07-14 RYR98YP STN → MLA Jul 14, 12:40 UTCJul 14, 14:40 UTC2h 0m
2026-07-14 RYR5TL - Jul 14, 10:20 UTCJul 14, 11:40 UTC1h 20m
2026-07-14 RYR46CU - Jul 14, 07:50 UTCJul 14, 09:30 UTC1h 40m
2026-07-14 RYR4ZJ AHO → PSA Jul 14, 05:45 UTCJul 14, 06:30 UTC45m
2026-07-14 RYR7992 - Jul 14, 04:05 UTCJul 14, 04:50 UTC45m
2026-07-13 RYR1282 - Jul 13, 19:15 UTCJul 13, 21:30 UTC2h 15m
2026-07-13 RYR1281 PSA → TRF Jul 13, 16:05 UTCJul 13, 18:25 UTC2h 20m
2026-07-13 RYR5AD - Jul 13, 14:00 UTCJul 13, 15:15 UTC1h 15m
2026-07-13 RYR28SP - Jul 13, 11:40 UTCJul 13, 12:45 UTC1h 5m
2026-07-13 RYR5NB - Jul 13, 09:30 UTCJul 13, 10:30 UTC1h 0m
2026-07-13 RYR761H - Jul 13, 07:45 UTCJul 13, 08:45 UTC1h 0m
2026-07-13 RYR2WF - Jul 13, 05:55 UTCJul 13, 06:55 UTC1h 0m
2026-07-13 RYR32RL - Jul 13, 04:10 UTCJul 13, 05:01 UTC50m
2026-07-12 RYR7LG - Jul 12, 20:25 UTCJul 12, 21:35 UTC1h 10m
2026-07-12 RYR30KW - Jul 12, 18:35 UTCJul 12, 19:40 UTC1h 5m
2026-07-12 RYR716U - Jul 12, 16:25 UTCJul 12, 17:40 UTC1h 15m
2026-07-12 RYR19SG - Jul 12, 14:25 UTCJul 12, 15:35 UTC1h 10m
2026-07-12 RYR98XK - Jul 12, 12:01 UTCJul 12, 13:15 UTC1h 15m
2026-07-12 RYR838P - Jul 12, 09:45 UTCJul 12, 11:10 UTC1h 25m
2026-07-12 RYR66DP - Jul 12, 07:20 UTCJul 12, 09:00 UTC1h 40m
2026-07-12 RYR83TK - Jul 12, 04:35 UTCJul 12, 06:25 UTC1h 50m
2026-07-11 RYR81 - Jul 11, 20:50 UTCJul 11, 22:10 UTC1h 20m
2026-07-11 RYR67EY - Jul 11, 18:10 UTCJul 11, 19:35 UTC1h 25m
2026-07-11 RYR8LB - Jul 11, 15:30 UTCJul 11, 17:25 UTC1h 55m
2026-07-11 RYR6QH PMI → BER Jul 11, 13:20 UTCJul 11, 14:05 UTC45m
2026-07-11 RYR51GN CFU → NAP Jul 11, 11:25 UTCJul 11, 12:05 UTC40m
2026-07-11 RYR984D - Jul 11, 08:01 UTCJul 11, 10:00 UTC2h 0m
2026-07-11 RYR6969 - Jul 11, 04:25 UTCJul 11, 06:35 UTC2h 10m
2026-07-10 RYR1YG - Jul 10, 19:15 UTCJul 10, 20:10 UTC55m
2026-07-10 RYR7565 - Jul 10, 17:30 UTCJul 10, 18:25 UTC55m
2026-07-10 RYR5FY - Jul 10, 15:20 UTCJul 10, 16:15 UTC55m
2026-07-10 RYR2CV AGP → MRS Jul 10, 13:00 UTCJul 10, 14:05 UTC1h 5m
2026-07-10 RYR6978 - Jul 10, 09:40 UTCJul 10, 11:15 UTC1h 35m
2026-07-10 RYR6977 CFU → FKB Jul 10, 07:00 UTCJul 10, 08:55 UTC1h 55m
2026-07-10 RYR9DR - Jul 10, 05:15 UTCJul 10, 05:45 UTC30m
2026-07-10 RYR1235 - Jul 10, 03:25 UTCJul 10, 03:55 UTC30m
2026-07-09 RYR67 - Jul 9, 20:05 UTCJul 9, 20:35 UTC30m
2026-07-09 RYR38BV - Jul 9, 18:35 UTCJul 9, 19:05 UTC30m
2026-07-09 RYR73YH - Jul 9, 16:00 UTCJul 9, 17:10 UTC1h 10m
2026-07-09 RYR6JU - Jul 9, 13:15 UTCJul 9, 14:40 UTC1h 25m
2026-07-09 RYR1152 - Jul 9, 10:20 UTCJul 9, 11:25 UTC1h 5m
2026-07-09 RYR1153 - Jul 9, 07:30 UTCJul 9, 08:50 UTC1h 20m
2026-07-09 RYR8054 - Jul 9, 05:15 UTCJul 9, 06:10 UTC55m
2026-07-09 RYR5CJ - Jul 9, 03:15 UTCJul 9, 04:30 UTC1h 15m

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

Mode-S 4D21E9 frequently asked

What is Mode-S code 4D21E9?
4D21E9 is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-QAA.
Where is Mode-S 4D21E9 registered?
Mode-S code 4D21E9 is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21E9 broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21E9, octal 23220751, decimal 5,054,953.
What flights does 4D21E9 operate?
Mode-S 4D21E9 has broadcast 20 distinct callsigns, including RYR738U, RYR6FR, RYR2BD, RYR2A, RYR1237.