Apparatus

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sensors Mode-S transponder

C81594

ICAO 24-bit transponder address · allocated to New Zealand

Currently assigned to ZK-TZH · ROBIN HR-200

Hex
C81594
Octal
62012624
Decimal
13,112,724
Country
NZ
Tail
ZK-TZH
Type
HR20
No current signal · last broadcast 23h ago
Flights observed
8
Distinct callsigns
1
Country
NZ
Last broadcast
23h ago

Last known position

Most recent position reported by Mode-S C81594.

Country allocation

The ICAO 24-bit address C81594 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
ZKTZH - 8 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 ZKTZH - Apr 13, 22:10 UTCApr 13, 23:35 UTC1h 25m
2026-04-13 ZKTZH - Apr 13, 20:35 UTCApr 13, 21:25 UTC50m
2026-04-13 ZKTZH - Apr 13, 05:45 UTCApr 13, 06:05 UTC20m
2026-04-13 ZKTZH - Apr 13, 04:20 UTCApr 13, 05:05 UTC45m
2026-04-13 ZKTZH - Apr 13, 04:10 UTCApr 13, 05:05 UTC55m
2026-04-13 ZKTZH - Apr 13, 00:20 UTCApr 13, 00:30 UTC10m
2026-04-13 ZKTZH - Apr 13, 00:10 UTCApr 13, 00:30 UTC20m
2026-04-12 ZKTZH - Apr 12, 19:55 UTCApr 12, 20:15 UTC20m

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

Mode-S C81594 frequently asked

What is Mode-S code C81594?
C81594 is an ICAO 24-bit transponder address. Allocated to New Zealand. Assigned to ZK-TZH.
Where is Mode-S C81594 registered?
Mode-S code C81594 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 C81594 broadcasting right now?
No active broadcast right now. Last signal was 23h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex C81594, octal 62012624, decimal 13,112,724.
What flights does C81594 operate?
Mode-S C81594 has broadcast 1 distinct callsign, including ZKTZH.