sensors Mode-S transponder

C81A1C

ICAO 24-bit transponder address · allocated to New Zealand

Currently assigned to ZK-TZM · ROBIN Alpha

Hex
C81A1C
Octal
62015034
Decimal
13,113,884
Country
NZ
Tail
ZK-TZM
Type
R200
No current signal · last broadcast 1d ago
Flights observed
5
Distinct callsigns
1
Country
NZ
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S C81A1C.

Country allocation

The ICAO 24-bit address C81A1C 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 1 distinct

Callsign Airline Flights Last seen
ZKTZM - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 ZKTZM - Apr 13, 20:25 UTCApr 13, 23:05 UTC2h 40m
2026-04-13 ZKTZM - Apr 13, 04:50 UTCApr 13, 05:15 UTC25m
2026-04-13 ZKTZM - Apr 13, 04:05 UTCApr 13, 04:15 UTC10m
2026-04-13 ZKTZM - Apr 13, 03:25 UTCApr 13, 04:15 UTC50m
2026-04-13 ZKTZM - Apr 13, 00:50 UTCApr 13, 01:25 UTC35m

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

Mode-S C81A1C frequently asked

What is Mode-S code C81A1C?
C81A1C is an ICAO 24-bit transponder address. Allocated to New Zealand. Assigned to ZK-TZM.
Where is Mode-S C81A1C registered?
Mode-S code C81A1C 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 C81A1C 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 C81A1C, octal 62015034, decimal 13,113,884.
What flights does C81A1C operate?
Mode-S C81A1C has broadcast 1 distinct callsign, including ZKTZM.