sensors Mode-S transponder

4D21BC

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-ASB · BOMBARDIER BD-700 Global 5000/5500

Hex
4D21BC
Octal
23220674
Decimal
5,054,908
Country
MT
Tail
9H-ASB
Type
GL5T
No current signal · last broadcast 1d ago
Flights observed
31
Distinct callsigns
1
Country
MT
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 4D21BC.

Country allocation

The ICAO 24-bit address 4D21BC 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 1 distinct

Callsign Airline Flights Last seen
HYP247 - 31 2026-06-01

Recent flights last 31

DateFlightRouteTakeoffLandingDuration
2026-06-01 HYP247 - Jun 1, 04:15 UTCJun 1, 06:10 UTC1h 55m
2026-05-31 HYP247 - May 31, 20:25 UTCJun 1, 03:05 UTC6h 40m
2026-05-25 HYP247 - May 25, 11:05 UTCMay 25, 11:35 UTC30m
2026-05-22 HYP247 - May 22, 23:30 UTCMay 23, 00:25 UTC55m
2026-05-22 HYP247 - May 22, 20:15 UTCMay 22, 22:10 UTC1h 55m
2026-05-14 HYP247 - May 14, 13:15 UTCMay 14, 18:20 UTC5h 5m
2026-05-13 HYP247 - May 13, 07:40 UTCMay 13, 11:45 UTC4h 5m
2026-05-10 HYP247 - May 10, 15:09 UTCMay 10, 17:49 UTC2h 40m
2026-05-09 HYP247 - May 9, 09:40 UTCMay 9, 12:10 UTC2h 30m
2026-05-08 HYP247 - May 8, 11:44 UTCMay 8, 13:35 UTC1h 50m
2026-05-07 HYP247 - May 7, 03:30 UTCMay 7, 11:35 UTC8h 6m
2026-05-04 HYP247 - May 4, 18:05 UTCMay 5, 03:15 UTC9h 11m
2026-05-04 HYP247 - May 4, 15:45 UTCMay 4, 17:15 UTC1h 30m
2026-05-02 HYP247 - May 2, 08:45 UTCMay 2, 10:10 UTC1h 25m
2026-04-26 HYP247 - Apr 26, 11:25 UTCApr 26, 11:50 UTC25m
2026-04-25 HYP247 - Apr 25, 18:05 UTCApr 25, 21:10 UTC3h 5m
2026-04-25 HYP247 - Apr 25, 16:50 UTCApr 25, 17:10 UTC20m
2026-04-24 HYP247 - Apr 24, 05:05 UTCApr 24, 06:00 UTC55m
2026-04-23 HYP247 - Apr 23, 23:10 UTCApr 23, 23:25 UTC15m
2026-04-22 HYP247 - Apr 22, 18:20 UTCApr 22, 18:55 UTC35m
2026-04-21 HYP247 - Apr 21, 22:50 UTCApr 22, 01:00 UTC2h 10m
2026-04-19 HYP247 - Apr 19, 16:55 UTCApr 19, 19:30 UTC2h 35m
2026-04-19 HYP247 - Apr 19, 13:30 UTCApr 19, 14:00 UTC30m
2026-04-16 HYP247 - Apr 16, 09:39 UTCApr 16, 10:09 UTC30m
2026-04-16 HYP247 - Apr 16, 07:09 UTCApr 16, 08:30 UTC1h 20m
2026-04-16 HYP247 - Apr 16, 05:09 UTCApr 16, 07:05 UTC1h 55m
2026-04-16 HYP247 - Apr 16, 04:49 UTCApr 16, 05:05 UTC15m
2026-04-14 HYP247 - Apr 14, 22:55 UTCApr 14, 23:25 UTC30m
2026-04-14 HYP247 - Apr 14, 20:55 UTCApr 14, 22:50 UTC1h 55m
2026-04-14 HYP247 - Apr 14, 18:55 UTCApr 14, 20:50 UTC1h 55m
2026-04-13 HYP247 - Apr 13, 21:10 UTCApr 13, 23:40 UTC2h 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-ASB page for operator, model, and routing details .

Mode-S 4D21BC frequently asked

What is Mode-S code 4D21BC?
4D21BC is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-ASB.
Where is Mode-S 4D21BC registered?
Mode-S code 4D21BC is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21BC broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21BC, octal 23220674, decimal 5,054,908.
What flights does 4D21BC operate?
Mode-S 4D21BC has broadcast 1 distinct callsign, including HYP247.