sensors Mode-S transponder

4AB821

ICAO 24-bit transponder address · allocated to Sweden

Currently assigned to SE-NAA · BOEING 737 MAX 8

Hex
4AB821
Octal
22534041
Decimal
4,896,801
Country
SE
Tail
SE-NAA
Type
B38M
No current signal · last broadcast 17h ago
Flights observed
14
Distinct callsigns
10
Country
SE
Last broadcast
17h ago

Last known position

Most recent position reported by Mode-S 4AB821.

Country allocation

The ICAO 24-bit address 4AB821 falls within the block assigned to Sweden (SE) by ICAO Annex 10, Volume III. Every aircraft registered in Sweden 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 10 distinct

Callsign Airline Flights Last seen
NSZ3510 - 2 2026-04-13
NSZ3503 - 2 2026-04-13
NSZ3502 Norwegian Air Sweden AOC 2 2026-04-13
NSZ3390 Norwegian Air Sweden AOC 2 2026-04-14
NSZ5TP - 1 2026-04-13
NSZ4KP - 1 2026-04-13
NSZ3646 - 1 2026-04-13
NSZ3391 Norwegian Air Sweden AOC 1 2026-04-14
NSZ3234 - 1 2026-04-12
NSZ3231 - 1 2026-04-12

Recent flights last 14

DateFlightRouteTakeoffLandingDuration
2026-04-14 NSZ3391 LCA → CPH Apr 14, 09:10 UTCApr 14, 11:05 UTC1h 55m
2026-04-14 NSZ3390 CPH → LCA Apr 14, 07:10 UTCApr 14, 07:45 UTC35m
2026-04-14 NSZ3390 CPH → LCA Apr 14, 05:15 UTCApr 14, 07:10 UTC1h 55m
2026-04-13 NSZ4KP - Apr 13, 20:00 UTCApr 13, 20:10 UTC10m
2026-04-13 NSZ3646 - Apr 13, 17:05 UTCApr 13, 19:10 UTC2h 5m
2026-04-13 NSZ3503 - Apr 13, 15:50 UTCApr 13, 16:10 UTC20m
2026-04-13 NSZ3503 - Apr 13, 14:45 UTCApr 13, 16:10 UTC1h 25m
2026-04-13 NSZ3502 CPH → EDI Apr 13, 12:20 UTCApr 13, 13:20 UTC1h 0m
2026-04-13 NSZ3502 CPH → EDI Apr 13, 11:45 UTCApr 13, 12:15 UTC30m
2026-04-13 NSZ5TP - Apr 13, 09:05 UTCApr 13, 10:30 UTC1h 25m
2026-04-13 NSZ3510 - Apr 13, 07:55 UTCApr 13, 08:00 UTC5m
2026-04-13 NSZ3510 - Apr 13, 06:15 UTCApr 13, 08:00 UTC1h 45m
2026-04-12 NSZ3234 - Apr 12, 18:40 UTCApr 12, 19:35 UTC55m
2026-04-12 NSZ3231 - Apr 12, 17:15 UTCApr 12, 17:45 UTC30m

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 SE-NAA page for operator, model, and routing details .

Mode-S 4AB821 frequently asked

What is Mode-S code 4AB821?
4AB821 is an ICAO 24-bit transponder address. Allocated to Sweden. Assigned to SE-NAA.
Where is Mode-S 4AB821 registered?
Mode-S code 4AB821 is allocated to Sweden (SE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4AB821 broadcasting right now?
No active broadcast right now. Last signal was 17h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4AB821, octal 22534041, decimal 4,896,801.
What flights does 4AB821 operate?
Mode-S 4AB821 has broadcast 10 distinct callsigns, including NSZ3510, NSZ3503, NSZ3502, NSZ3390, NSZ5TP.