Apparatus

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sensors Mode-S transponder

C81A1B

ICAO 24-bit transponder address · allocated to New Zealand

Currently assigned to ZK-SAN · CESSNA 208 Caravan

Hex
C81A1B
Octal
62015033
Decimal
13,113,883
Country
NZ
Tail
ZK-SAN
Type
C208
No current signal · last broadcast 2h ago
Flights observed
252
Distinct callsigns
20
Country
NZ
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S C81A1B.

Country allocation

The ICAO 24-bit address C81A1B falls within the block assigned to New Zealand (NZ) by ICAO Annex 10, Volume III. Every aircraft registered in New Zealand 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 20 distinct

Callsign Airline Flights Last seen
SDA347 Sounds Air 11 2026-05-29
SDA341 Sounds Air 11 2026-05-29
SDA345 Sounds Air 10 2026-05-28
SDA342 Sounds Air 9 2026-05-29
SDA346 Sounds Air 8 2026-05-30
SDA349 Sounds Air 7 2026-05-29
SDA357 Sounds Air 6 2026-05-24
SDA343 Sounds Air 6 2026-05-25
SDA358 Sounds Air 5 2026-05-24
SDA350 Sounds Air 5 2026-05-29
SDA348 Sounds Air 5 2026-05-29
SDA287 Sounds Air 5 2026-05-26
SDA282 Sounds Air 5 2026-05-27
SDA253 Sounds Air 5 2026-05-29
SDA251 Sounds Air 5 2026-05-15
SDA359 Sounds Air 4 2026-05-24
SDA351 Sounds Air 4 2026-05-18
SDA285 Sounds Air 4 2026-05-26
SDA283 Sounds Air 4 2026-05-27
SDA281 Sounds Air 4 2026-05-27

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 SDA346 NSN → WLG May 30, 03:45 UTCMay 30, 03:55 UTC10m
2026-05-30 SDA214 BHE → WLG May 30, 01:30 UTCMay 30, 02:20 UTC50m
2026-05-29 SDA253 WLG → BHE May 29, 21:25 UTCMay 29, 21:40 UTC15m
2026-05-29 SDA342 NSN → WLG May 29, 20:25 UTCMay 29, 20:35 UTC10m
2026-05-29 SDA341 WLG → NSN May 29, 19:00 UTCMay 29, 19:10 UTC10m
2026-05-29 SDA350 NSN → WLG May 29, 08:35 UTCMay 29, 08:50 UTC15m
2026-05-29 SDA349 WLG → NSN May 29, 07:00 UTCMay 29, 07:20 UTC20m
2026-05-29 SDA348 NSN → WLG May 29, 06:00 UTCMay 29, 06:15 UTC15m
2026-05-29 SDA347 WLG → NSN May 29, 04:25 UTCMay 29, 04:50 UTC25m
2026-05-29 SDA275 WLG → BHE May 29, 02:20 UTCMay 29, 02:40 UTC20m
2026-05-28 SDA410 - May 28, 22:05 UTCMay 28, 22:40 UTC35m
2026-05-28 SDA272 - May 28, 19:50 UTCMay 28, 20:05 UTC15m
2026-05-28 SDA271 WLG → BHE May 28, 18:40 UTCMay 28, 18:50 UTC10m
2026-05-28 SDA349 WLG → NSN May 28, 06:55 UTCMay 28, 07:40 UTC45m
2026-05-28 SDA347 WLG → NSN May 28, 04:55 UTCMay 28, 05:35 UTC40m
2026-05-28 SDA345 WLG → NSN May 28, 03:00 UTCMay 28, 03:15 UTC15m
2026-05-27 SDA283 WLG → BHE May 27, 23:05 UTCMay 27, 23:20 UTC15m
2026-05-27 SDA282 BHE → WLG May 27, 19:45 UTCMay 27, 19:55 UTC10m
2026-05-27 SDA281 WLG → BHE May 27, 18:15 UTCMay 27, 19:00 UTC45m
2026-05-26 SDA289 WLG → BHE May 26, 06:39 UTCMay 26, 07:34 UTC55m
2026-05-26 SDA287 WLG → BHE May 26, 04:50 UTCMay 26, 05:40 UTC50m
2026-05-26 SDA285 WLG → BHE May 26, 03:45 UTCMay 26, 03:55 UTC10m
2026-05-26 SDA345 WLG → NSN May 26, 01:05 UTCMay 26, 01:20 UTC15m
2026-05-25 SDA343 WLG → NSN May 25, 20:40 UTCMay 25, 20:50 UTC10m
2026-05-25 SDA282 BHE → WLG May 25, 19:50 UTCMay 25, 19:59 UTC10m
2026-05-25 SDA280 BHE → WLG May 25, 18:10 UTCMay 25, 19:00 UTC50m
2026-05-25 SDA255 WLG → BHE May 25, 06:20 UTCMay 25, 06:30 UTC10m
2026-05-25 SDA116 BHE → WLG May 25, 03:50 UTCMay 25, 04:00 UTC10m
2026-05-25 SDA115 WLG → BHE May 25, 02:50 UTCMay 25, 03:05 UTC15m
2026-05-24 SDA344 NSN → WLG May 24, 21:10 UTCMay 24, 21:20 UTC10m
2026-05-24 SDA343 WLG → NSN May 24, 19:40 UTCMay 24, 20:00 UTC20m
2026-05-24 SDA360 NSN → WLG May 24, 07:35 UTCMay 24, 07:50 UTC15m
2026-05-24 SDA359 WLG → NSN May 24, 06:05 UTCMay 24, 06:20 UTC15m
2026-05-24 SDA358 NSN → WLG May 24, 04:55 UTCMay 24, 05:15 UTC20m
2026-05-24 SDA357 WLG → NSN May 24, 02:50 UTCMay 24, 03:40 UTC50m
2026-05-23 SDA213 WLG → BHE May 23, 00:05 UTCMay 23, 00:20 UTC15m
2026-05-22 SDA212 BHE → WLG May 22, 21:10 UTCMay 22, 21:25 UTC15m
2026-05-22 SDA270 BHE → WLG May 22, 19:15 UTCMay 22, 20:05 UTC50m
2026-05-22 SDA268 BHE → WLG May 22, 08:30 UTCMay 22, 09:00 UTC30m
2026-05-22 SDA267 WLG → BHE May 22, 06:55 UTCMay 22, 07:35 UTC40m
2026-05-21 SDA263 WLG → BHE May 21, 22:30 UTCMay 21, 23:20 UTC50m
2026-05-21 SDA261 WLG → BHE May 21, 21:30 UTCMay 21, 21:45 UTC15m
2026-05-21 SDA341 WLG → NSN May 21, 19:00 UTCMay 21, 19:20 UTC20m
2026-05-21 SDA260 BHE → WLG May 21, 18:15 UTCMay 21, 18:25 UTC10m
2026-05-20 SDA243 WLG → BHE May 20, 00:05 UTCMay 20, 00:25 UTC20m
2026-05-19 SDA242 BHE → WLG May 19, 21:35 UTCMay 19, 21:45 UTC10m
2026-05-19 SDA241 WLG → BHE May 19, 20:30 UTCMay 19, 20:50 UTC20m
2026-05-19 SDA342 NSN → WLG May 19, 19:25 UTCMay 19, 19:35 UTC10m
2026-05-19 SDA341 WLG → NSN May 19, 18:00 UTCMay 19, 18:10 UTC10m
2026-05-19 SDA350 NSN → WLG May 19, 08:25 UTCMay 19, 08:35 UTC10m

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 ZK-SAN page for operator, model, and routing details .

Mode-S C81A1B frequently asked

What is Mode-S code C81A1B?
C81A1B is an ICAO 24-bit transponder address. Allocated to New Zealand. Assigned to ZK-SAN.
Where is Mode-S C81A1B registered?
Mode-S code C81A1B is allocated to New Zealand (NZ). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is C81A1B broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex C81A1B, octal 62015033, decimal 13,113,883.
What flights does C81A1B operate?
Mode-S C81A1B has broadcast 20 distinct callsigns, including SDA347, SDA341, SDA345, SDA342, SDA346.