sensors Mode-S transponder

4D203B

ICAO 24-bit transponder address · allocated to Malta

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

Hex
4D203B
Octal
23220073
Decimal
5,054,523
Country
MT
Tail
9H-ISM
Type
B738
Broadcasting now · callsign BBG253 · 39,000 ft
Flights observed
5
Distinct callsigns
5
Country
MT
Last broadcast
25m ago

Current position

4D203B is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4D203B 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 5 distinct

Callsign Airline Flights Last seen
BBG747 - 1 2026-04-22
BBG746 - 1 2026-04-22
BBG745 - 1 2026-04-22
BBG253 Bluebird Airways (BZ) 1 2026-04-22
BBG252 - 1 2026-04-22

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-22 BBG253 BCN → TLV Apr 22, 22:15 UTCApr 23, 00:45 UTC2h 30m
2026-04-22 BBG252 - Apr 22, 13:05 UTCApr 22, 16:50 UTC3h 45m
2026-04-22 BBG745 - Apr 22, 09:30 UTCApr 22, 10:45 UTC1h 15m
2026-04-22 BBG746 - Apr 22, 05:30 UTCApr 22, 06:40 UTC1h 10m
2026-04-22 BBG747 - Apr 22, 03:20 UTCApr 22, 04:30 UTC1h 10m

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

Mode-S 4D203B frequently asked

What is Mode-S code 4D203B?
4D203B is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-ISM.
Where is Mode-S 4D203B registered?
Mode-S code 4D203B is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D203B broadcasting right now?
Yes. Mode-S 4D203B is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D203B, octal 23220073, decimal 5,054,523.
What flights does 4D203B operate?
Mode-S 4D203B has broadcast 5 distinct callsigns, including BBG747, BBG746, BBG745, BBG253, BBG252.