sensors Mode-S transponder

4D21EE

ICAO 24-bit transponder address · allocated to Malta

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

Hex
4D21EE
Octal
23220756
Decimal
5,054,958
Country
MT
Tail
9H-QAF
Type
B738
No current signal · last broadcast 20h ago
Flights observed
16
Distinct callsigns
11
Country
MT
Last broadcast
20h ago

Last known position

Most recent position reported by Mode-S 4D21EE.

Country allocation

The ICAO 24-bit address 4D21EE 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 11 distinct

Callsign Airline Flights Last seen
RYR84SX - 2 2026-04-14
RYR44GP - 2 2026-04-13
RYR41MD - 2 2026-04-13
RYR2FF - 2 2026-04-13
RYR161N - 2 2026-04-14
RYR60SF - 1 2026-04-13
RYR5WD - 1 2026-04-12
RYR46UC - 1 2026-04-12
RYR41ZK Ryanair 1 2026-04-13
RYR41UD - 1 2026-04-13
RYR38MM - 1 2026-04-14

Recent flights last 16

DateFlightRouteTakeoffLandingDuration
2026-04-14 RYR38MM BTS → BZO Apr 14, 10:25 UTCApr 14, 11:05 UTC40m
2026-04-14 RYR84SX - Apr 14, 09:10 UTCApr 14, 09:45 UTC35m
2026-04-14 RYR84SX - Apr 14, 08:35 UTCApr 14, 09:05 UTC30m
2026-04-14 RYR161N - Apr 14, 07:10 UTCApr 14, 07:40 UTC30m
2026-04-14 RYR161N - Apr 14, 06:30 UTCApr 14, 07:10 UTC40m
2026-04-13 RYR44GP - Apr 13, 19:50 UTCApr 13, 21:25 UTC1h 35m
2026-04-13 RYR44GP - Apr 13, 19:35 UTCApr 13, 20:10 UTC35m
2026-04-13 RYR60SF MXP → MAN Apr 13, 17:05 UTCApr 13, 18:50 UTC1h 45m
2026-04-13 RYR2FF - Apr 13, 15:50 UTCApr 13, 16:05 UTC15m
2026-04-13 RYR2FF - Apr 13, 14:40 UTCApr 13, 16:05 UTC1h 25m
2026-04-13 RYR41MD - Apr 13, 12:20 UTCApr 13, 13:35 UTC1h 15m
2026-04-13 RYR41MD - Apr 13, 12:05 UTCApr 13, 12:15 UTC10m
2026-04-13 RYR41ZK BDS → MXP Apr 13, 08:40 UTCApr 13, 09:50 UTC1h 10m
2026-04-13 RYR41UD - Apr 13, 06:15 UTCApr 13, 07:20 UTC1h 5m
2026-04-12 RYR46UC - Apr 12, 20:05 UTCApr 12, 20:15 UTC10m
2026-04-12 RYR5WD - Apr 12, 18:05 UTCApr 12, 19:00 UTC55m

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

Mode-S 4D21EE frequently asked

What is Mode-S code 4D21EE?
4D21EE is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-QAF.
Where is Mode-S 4D21EE registered?
Mode-S code 4D21EE is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21EE broadcasting right now?
No active broadcast right now. Last signal was 20h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21EE, octal 23220756, decimal 5,054,958.
What flights does 4D21EE operate?
Mode-S 4D21EE has broadcast 11 distinct callsigns, including RYR84SX, RYR44GP, RYR41MD, RYR2FF, RYR161N.