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sensors Mode-S transponder

4D21AA

ICAO 24-bit transponder address · allocated to Malta

Currently assigned to 9H-MPA · BOMBARDIER Regional Jet CRJ-1000

Hex
4D21AA
Octal
23220652
Decimal
5,054,890
Country
MT
Tail
9H-MPA
Type
CRJX
No current signal · last broadcast 9d ago
Flights observed
62
Distinct callsigns
9
Country
MT
Last broadcast
9d ago

Last known position

Most recent position reported by Mode-S 4D21AA.

Country allocation

The ICAO 24-bit address 4D21AA 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 9 distinct

Callsign Airline Flights Last seen
AAE158 - 27 2026-07-24
AAE157 - 16 2026-07-24
AAE154 - 6 2026-06-22
AAE153 - 4 2026-06-22
AAE143 - 2 2026-07-04
AAE142 - 2 2026-07-04
AAE141 - 2 2026-07-03
AAE101 - 2 2026-06-17
AAE032P - 1 2026-05-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-24 AAE158 - Jul 24, 22:15 UTCJul 25, 10:20 UTC12h 5m
2026-07-24 AAE158 - Jul 24, 10:35 UTCJul 25, 10:20 UTC23h 45m
2026-07-24 AAE157 - Jul 24, 09:15 UTCJul 25, 08:20 UTC23h 5m
2026-07-24 AAE158 - Jul 24, 01:45 UTCJul 24, 04:50 UTC3h 5m
2026-07-22 AAE157 - Jul 22, 04:35 UTCJul 22, 05:25 UTC50m
2026-07-21 AAE158 - Jul 21, 04:30 UTCJul 21, 07:45 UTC3h 15m
2026-07-19 AAE157 - Jul 19, 21:10 UTCJul 19, 22:35 UTC1h 25m
2026-07-19 AAE158 - Jul 19, 03:00 UTCJul 19, 06:10 UTC3h 10m
2026-07-18 AAE157 - Jul 18, 04:35 UTCJul 19, 04:15 UTC23h 40m
2026-07-16 AAE158 - Jul 16, 03:30 UTCJul 16, 06:40 UTC3h 10m
2026-07-14 AAE157 - Jul 14, 20:45 UTCJul 14, 22:05 UTC1h 20m
2026-07-14 AAE158 - Jul 14, 12:15 UTCJul 14, 15:35 UTC3h 20m
2026-07-13 AAE158 - Jul 13, 16:35 UTCJul 14, 15:35 UTC23h 0m
2026-07-13 AAE158 - Jul 13, 14:35 UTCJul 14, 13:35 UTC23h 0m
2026-07-13 AAE157 - Jul 13, 13:40 UTCJul 14, 12:30 UTC22h 50m
2026-07-13 AAE158 - Jul 13, 09:30 UTCJul 13, 09:35 UTC5m
2026-07-13 AAE158 - Jul 13, 06:25 UTCJul 13, 07:40 UTC1h 15m
2026-07-12 AAE158 - Jul 12, 08:35 UTCJul 13, 07:40 UTC23h 5m
2026-07-12 AAE157 - Jul 12, 07:31 UTCJul 13, 06:30 UTC23h 0m
2026-07-09 AAE158 - Jul 9, 05:55 UTCJul 9, 09:05 UTC3h 10m
2026-07-08 AAE157 - Jul 8, 06:35 UTCJul 9, 06:30 UTC23h 55m
2026-07-07 AAE158 - Jul 7, 04:15 UTCJul 7, 07:25 UTC3h 10m
2026-07-06 AAE158 - Jul 6, 06:55 UTCJul 7, 05:35 UTC22h 40m
2026-07-06 AAE157 - Jul 6, 04:50 UTCJul 7, 04:30 UTC23h 40m
2026-07-05 AAE158 - Jul 5, 17:40 UTCJul 5, 18:55 UTC1h 15m
2026-07-04 AAE143 - Jul 4, 18:35 UTCJul 5, 18:30 UTC23h 55m
2026-07-04 AAE143 - Jul 4, 17:50 UTCJul 4, 20:40 UTC2h 50m
2026-07-04 AAE142 - Jul 4, 08:20 UTCJul 4, 13:30 UTC5h 10m
2026-07-03 AAE142 - Jul 3, 21:20 UTCJul 3, 21:40 UTC20m
2026-07-03 AAE141 - Jul 3, 18:05 UTCJul 3, 18:30 UTC25m
2026-07-03 AAE141 - Jul 3, 08:00 UTCJul 3, 10:50 UTC2h 50m
2026-07-02 AAE158 - Jul 2, 01:40 UTCJul 2, 04:45 UTC3h 5m
2026-07-01 AAE158 - Jul 1, 06:35 UTCJul 2, 04:45 UTC22h 10m
2026-07-01 AAE158 - Jul 1, 04:35 UTCJul 2, 04:30 UTC23h 55m
2026-07-01 AAE157 - Jul 1, 04:00 UTCJul 2, 02:30 UTC22h 30m
2026-06-30 AAE158 - Jun 30, 09:45 UTCJun 30, 12:50 UTC3h 5m
2026-06-29 AAE157 - Jun 29, 10:34 UTCJun 30, 10:30 UTC23h 56m
2026-06-29 AAE157 - Jun 29, 09:20 UTCJun 29, 12:05 UTC2h 45m
2026-06-29 AAE158 - Jun 29, 00:14 UTCJun 29, 03:25 UTC3h 10m
2026-06-27 AAE157 - Jun 27, 21:29 UTCJun 28, 00:15 UTC2h 45m
2026-06-27 AAE158 - Jun 27, 13:15 UTCJun 27, 16:24 UTC3h 10m
2026-06-26 AAE158 - Jun 26, 17:50 UTCJun 27, 16:24 UTC22h 35m
2026-06-26 AAE157 - Jun 26, 15:05 UTCJun 27, 14:29 UTC23h 25m
2026-06-26 AAE158 - Jun 26, 07:55 UTCJun 26, 11:05 UTC3h 10m
2026-06-25 AAE158 - Jun 25, 11:04 UTCJun 26, 10:30 UTC23h 25m
2026-06-25 AAE157 - Jun 25, 08:40 UTCJun 26, 08:30 UTC23h 50m
2026-06-24 AAE158 - Jun 24, 09:19 UTCJun 24, 12:25 UTC3h 5m
2026-06-23 AAE158 - Jun 23, 11:45 UTCJun 24, 10:25 UTC22h 40m
2026-06-23 AAE157 - Jun 23, 08:59 UTCJun 23, 11:49 UTC2h 50m
2026-06-22 AAE154 - Jun 22, 23:55 UTCJun 23, 03:15 UTC3h 20m

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

Mode-S 4D21AA frequently asked

What is Mode-S code 4D21AA?
4D21AA is an ICAO 24-bit transponder address. Allocated to Malta. Assigned to 9H-MPA.
Where is Mode-S 4D21AA registered?
Mode-S code 4D21AA is allocated to Malta (MT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4D21AA broadcasting right now?
No active broadcast right now. Last signal was 9d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4D21AA, octal 23220652, decimal 5,054,890.
What flights does 4D21AA operate?
Mode-S 4D21AA has broadcast 9 distinct callsigns, including AAE158, AAE157, AAE154, AAE153, AAE143.