sensors Mode-S transponder

84C051

ICAO 24-bit transponder address · allocated to Japan

Currently assigned to JA23HK · CIRRUS SR-22

Hex
84C051
Octal
41140121
Decimal
8,699,985
Country
JP
Tail
JA23HK
Type
SR22
No current signal · last broadcast 1d ago
Flights observed
1
Distinct callsigns
1
Country
JP
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 84C051.

Country allocation

The ICAO 24-bit address 84C051 falls within the block assigned to Japan (JP) by ICAO Annex 10, Volume III. Every aircraft registered in Japan 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
JA23HK - 1 2026-04-14

Recent flights last 1

DateFlightRouteTakeoffLandingDuration
2026-04-14 JA23HK - Apr 14, 05:40 UTCApr 14, 06:30 UTC50m

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 JA23HK page for operator, model, and routing details .

Mode-S 84C051 frequently asked

What is Mode-S code 84C051?
84C051 is an ICAO 24-bit transponder address. Allocated to Japan. Assigned to JA23HK.
Where is Mode-S 84C051 registered?
Mode-S code 84C051 is allocated to Japan (JP). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 84C051 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 84C051, octal 41140121, decimal 8,699,985.
What flights does 84C051 operate?
Mode-S 84C051 has broadcast 1 distinct callsign, including JA23HK.