sensors Mode-S transponder

4D21CC

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-OKO · GULFSTREAM G650

Hex
4D21CC
Octal
23220714
Decimal
5,054,924
Country
MT
Tail
9H-OKO
Type
GLF6
No current signal · last broadcast 2d ago
Flights observed
42
Distinct callsigns
2
Country
MT
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S 4D21CC.

Country allocation

The ICAO 24-bit address 4D21CC 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 2 distinct

Callsign Airline Flights Last seen
GSM650 - 41 2026-07-15
RYR40CR - 1 2026-06-28

Recent flights last 42

DateFlightRouteTakeoffLandingDuration
2026-07-15 GSM650 IBZ → HPN Jul 15, 14:40 UTCJul 15, 22:00 UTC7h 20m
2026-07-15 GSM650 VLC → IBZ Jul 15, 12:15 UTCJul 15, 12:50 UTC35m
2026-07-12 GSM650 - Jul 12, 21:25 UTCJul 12, 22:05 UTC40m
2026-07-12 GSM650 - Jul 12, 09:15 UTCJul 12, 20:45 UTC11h 30m
2026-07-11 GSM650 - Jul 11, 03:40 UTCJul 11, 08:01 UTC4h 20m
2026-07-08 GSM650 - Jul 8, 01:50 UTCJul 8, 03:35 UTC1h 45m
2026-07-06 GSM650 - Jul 6, 02:50 UTCJul 6, 07:45 UTC4h 55m
2026-07-03 GSM650 - Jul 3, 00:15 UTCJul 3, 10:55 UTC10h 40m
2026-07-02 GSM650 - Jul 2, 21:25 UTCJul 2, 22:15 UTC50m
2026-07-02 GSM650 - Jul 2, 10:00 UTCJul 2, 10:55 UTC55m
2026-07-02 GSM650 - Jul 2, 08:50 UTCJul 2, 09:40 UTC50m
2026-06-28 RYR40CR - Jun 28, 06:05 UTCJun 28, 06:30 UTC25m
2026-06-26 GSM650 - Jun 26, 18:15 UTCJun 26, 18:39 UTC25m
2026-06-26 GSM650 - Jun 26, 15:29 UTCJun 26, 17:25 UTC1h 55m
2026-06-21 GSM650 IBZ → BQH Jun 21, 09:20 UTCJun 21, 11:15 UTC1h 55m
2026-06-21 GSM650 - Jun 21, 07:00 UTCJun 21, 07:25 UTC25m
2026-06-19 GSM650 - Jun 19, 14:44 UTCJun 19, 15:04 UTC20m
2026-06-19 GSM650 ZRH → IBZ Jun 19, 12:39 UTCJun 19, 14:09 UTC1h 30m
2026-06-19 GSM650 IBZ → ZRH Jun 19, 08:50 UTCJun 19, 10:24 UTC1h 35m
2026-06-16 GSM650 - Jun 16, 18:05 UTCJun 16, 19:35 UTC1h 30m
2026-06-16 GSM650 - Jun 16, 10:00 UTCJun 16, 16:50 UTC6h 50m
2026-06-15 GSM650 - Jun 15, 19:10 UTCJun 15, 20:25 UTC1h 15m
2026-06-12 GSM650 SAV → SAV Jun 12, 20:20 UTCJun 12, 21:05 UTC45m
2026-06-10 GSM650 SAV → SAV Jun 10, 13:15 UTCJun 10, 13:20 UTC5m
2026-04-30 GSM650 - Apr 30, 20:25 UTCApr 30, 21:35 UTC1h 10m
2026-04-30 GSM650 - Apr 30, 11:25 UTCApr 30, 19:50 UTC8h 25m
2026-04-29 GSM650 - Apr 29, 21:45 UTCApr 29, 22:05 UTC20m
2026-04-29 GSM650 - Apr 29, 13:45 UTCApr 29, 20:50 UTC7h 5m
2026-04-29 GSM650 - Apr 29, 11:10 UTCApr 29, 11:25 UTC15m
2026-04-26 GSM650 - Apr 26, 18:30 UTCApr 26, 18:50 UTC20m
2026-04-26 GSM650 - Apr 26, 11:40 UTCApr 26, 17:30 UTC5h 50m
2026-04-24 GSM650 - Apr 24, 13:15 UTCApr 24, 15:20 UTC2h 5m
2026-04-22 GSM650 - Apr 22, 13:45 UTCApr 22, 16:45 UTC3h 0m
2026-04-20 GSM650 - Apr 20, 13:45 UTCApr 20, 15:10 UTC1h 25m
2026-04-18 GSM650 - Apr 18, 08:15 UTCApr 18, 11:45 UTC3h 30m
2026-04-18 GSM650 - Apr 18, 06:10 UTCApr 18, 06:25 UTC15m
2026-04-16 GSM650 - Apr 16, 21:14 UTCApr 16, 21:34 UTC20m
2026-04-16 GSM650 - Apr 16, 19:15 UTCApr 16, 20:30 UTC1h 15m
2026-04-16 GSM650 - Apr 16, 17:15 UTCApr 16, 19:10 UTC1h 55m
2026-04-15 GSM650 - Apr 15, 07:01 UTCApr 15, 07:45 UTC45m
2026-04-15 GSM650 - Apr 15, 06:20 UTCApr 15, 06:55 UTC35m
2026-04-15 GSM650 - Apr 15, 01:20 UTCApr 15, 02:50 UTC1h 30m

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

Mode-S 4D21CC frequently asked

What is Mode-S code 4D21CC?
4D21CC is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-OKO.
Where is Mode-S 4D21CC registered?
Mode-S code 4D21CC is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21CC broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21CC, octal 23220714, decimal 5,054,924.
What flights does 4D21CC operate?
Mode-S 4D21CC has broadcast 2 distinct callsigns, including GSM650, RYR40CR.