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
Transponder active on ground
Flights observed
695
Distinct callsigns
20
Country
MT
Last broadcast
Jul 26, 21:55 UTC

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
RYR83TK Ryanair 6 2026-07-25
RYR66DP Ryanair 6 2026-07-25
RYR9RN Ryanair 4 2026-07-26
RYR838P - 4 2026-07-19
RYR738U Ryanair 4 2026-05-27
RYR6FR Ryanair 4 2026-05-27
RYR5RZ Ryanair 4 2026-07-24
RYR54BY Ryanair 4 2026-07-26
RYR2BD - 4 2026-06-25
RYR2A Ryanair 4 2026-06-25
RYR1237 Ryanair 4 2026-06-25
RYR11EX - 4 2026-06-25
RYR9ZQ Ryanair 3 2026-07-24
RYR9JQ Ryanair 3 2026-06-06
RYR98XK - 3 2026-07-19
RYR98KN Ryanair 3 2026-07-22
RYR8RB - 3 2026-07-21
RYR8CV Ryanair 3 2026-07-26
RYR85AX Ryanair 3 2026-05-22
RYR80PC Ryanair 3 2026-05-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RYR54BY CTA → PSA Jul 26, 20:45 UTCJul 26, 21:55 UTC1h 10m
2026-07-26 RYR9RN PSA → CTA Jul 26, 18:40 UTCJul 26, 19:50 UTC1h 10m
2026-07-26 RYR2E STN → DUB Jul 26, 15:35 UTCJul 26, 17:00 UTC1h 25m
2026-07-26 RYR63XE - Jul 26, 13:20 UTCJul 26, 14:50 UTC1h 30m
2026-07-26 RYR4ZJ AHO → PSA Jul 26, 11:35 UTCJul 26, 12:10 UTC35m
2026-07-26 RYR7992 PSA → AHO Jul 26, 10:15 UTCJul 26, 10:55 UTC40m
2026-07-26 RYR6XK SNN → OPO Jul 26, 07:05 UTCJul 26, 09:10 UTC2h 5m
2026-07-26 RYR8CV PDV → MXP Jul 26, 04:10 UTCJul 26, 06:25 UTC2h 15m
2026-07-25 RYR20UU ALC → LPL Jul 25, 18:15 UTCJul 25, 19:35 UTC1h 20m
2026-07-25 RYR2KK RAK → DLE Jul 25, 16:00 UTCJul 25, 17:20 UTC1h 20m
2026-07-25 RYR11TX KUN → PSA Jul 25, 12:50 UTCJul 25, 15:00 UTC2h 10m
2026-07-25 RYR1809 PSA → KUN Jul 25, 10:00 UTCJul 25, 12:10 UTC2h 10m
2026-07-25 RYR66DP STN → PSA Jul 25, 07:25 UTCJul 25, 09:05 UTC1h 40m
2026-07-25 RYR83TK PSA → STN Jul 25, 04:20 UTCJul 25, 06:15 UTC1h 55m
2026-07-24 RYR54BY CTA → PSA Jul 24, 21:30 UTCJul 24, 22:40 UTC1h 10m
2026-07-24 RYR9RN PSA → CTA Jul 24, 19:05 UTCJul 24, 20:10 UTC1h 5m
2026-07-24 RYR9ZQ DUB → LTN Jul 24, 15:30 UTCJul 24, 18:10 UTC2h 40m
2026-07-24 RYR625N PSA → RHO Jul 24, 11:55 UTCJul 24, 14:05 UTC2h 10m
2026-07-24 RYR5RZ AGP → BVA Jul 24, 08:45 UTCJul 24, 10:20 UTC1h 35m
2026-07-24 RYR7276 - Jul 24, 05:35 UTCJul 24, 07:25 UTC1h 50m
2026-07-23 RYR66DP STN → PSA Jul 23, 20:55 UTCJul 23, 22:30 UTC1h 35m
2026-07-23 RYR83TK PSA → STN Jul 23, 17:50 UTCJul 23, 19:45 UTC1h 55m
2026-07-23 RYR1RH - Jul 23, 15:50 UTCJul 23, 16:50 UTC1h 0m
2026-07-23 RYR76CW - Jul 23, 13:55 UTCJul 23, 14:45 UTC50m
2026-07-23 RYR64XG KGS → PSA Jul 23, 10:10 UTCJul 23, 12:35 UTC2h 25m
2026-07-23 RYR80KK - Jul 23, 06:10 UTCJul 23, 08:10 UTC2h 0m
2026-07-22 RYR5EA BGY → NAP Jul 22, 20:05 UTCJul 22, 21:00 UTC55m
2026-07-22 RYR98KN PSA → PMO Jul 22, 17:55 UTCJul 22, 18:50 UTC55m
2026-07-22 RYR2ST MAN → FUE Jul 22, 15:20 UTCJul 22, 16:55 UTC1h 35m
2026-07-22 RYR2JF CRL → WMI Jul 22, 12:20 UTCJul 22, 14:25 UTC2h 5m
2026-07-22 RYR49RQ TIA → PSA Jul 22, 11:10 UTCJul 22, 11:20 UTC10m
2026-07-22 RYR7992 PSA → AHO Jul 22, 04:20 UTCJul 22, 05:00 UTC40m
2026-07-21 RYR8RB - Jul 21, 20:55 UTCJul 21, 21:35 UTC40m
2026-07-21 RYR292Q - Jul 21, 19:20 UTCJul 21, 19:55 UTC35m
2026-07-21 RYR3417 PIK → PSA Jul 21, 16:20 UTCJul 21, 18:30 UTC2h 10m
2026-07-21 RYR6DP STN → CIA Jul 21, 13:05 UTCJul 21, 15:25 UTC2h 20m
2026-07-21 RYR5NB - Jul 21, 10:15 UTCJul 21, 11:20 UTC1h 5m
2026-07-21 RYR761H - Jul 21, 08:30 UTCJul 21, 09:25 UTC55m
2026-07-21 RYR1KD - Jul 21, 06:20 UTCJul 21, 07:40 UTC1h 20m
2026-07-21 RYR6204 PSA → CTA Jul 21, 04:20 UTCJul 21, 05:20 UTC1h 0m
2026-07-20 RYR5EA - Jul 20, 21:40 UTCJul 20, 22:35 UTC55m
2026-07-20 RYR98KN PSA → PMO Jul 20, 19:45 UTCJul 20, 20:45 UTC1h 0m
2026-07-20 RYR82UJ - Jul 20, 17:30 UTCJul 20, 19:10 UTC1h 40m
2026-07-20 RYR4MT - Jul 20, 15:10 UTCJul 20, 16:35 UTC1h 25m
2026-07-20 RYR4KG - Jul 20, 12:10 UTCJul 20, 14:05 UTC1h 55m
2026-07-20 RYR88VF - Jul 20, 08:55 UTCJul 20, 10:30 UTC1h 35m
2026-07-20 RYR98 BTS → PSA Jul 20, 06:00 UTCJul 20, 07:15 UTC1h 15m
2026-07-20 RYR37UN PSA → BTS Jul 20, 04:05 UTCJul 20, 05:05 UTC1h 0m
2026-07-19 RYR7LG OPO → SNN Jul 19, 20:45 UTCJul 19, 21:55 UTC1h 10m
2026-07-19 RYR30KW PSA → BDS Jul 19, 18:55 UTCJul 19, 20:00 UTC1h 5m

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?
Mode-S 4D21E9 is currently broadcasting from the ground.
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 RYR83TK, RYR66DP, RYR9RN, RYR838P, RYR738U.