sensors Mode-S transponder

8681B7

ICAO 24-bit transponder address · allocated to Japan

Currently assigned to JA73NR · BOEING 737-800

Hex
8681B7
Octal
41500667
Decimal
8,815,031
Country
JP
Tail
JA73NR
Type
B738
No current signal · last broadcast 12h ago
Flights observed
11
Distinct callsigns
8
Country
JP
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S 8681B7.

Country allocation

The ICAO 24-bit address 8681B7 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 8 distinct

Callsign Airline Flights Last seen
SKY021 Skymark Airlines 3 2026-04-13
SKY520 Skymark Airlines 2 2026-04-14
SKY557 - 1 2026-04-14
SKY513 - 1 2026-04-13
SKY022 - 1 2026-04-13
SKY012 - 1 2026-04-13
SKY009 - 1 2026-04-13
SKY004 - 1 2026-04-13

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-14 SKY520 OKA → HND Apr 14, 09:40 UTCApr 14, 10:25 UTC45m
2026-04-14 SKY520 OKA → HND Apr 14, 08:25 UTCApr 14, 08:40 UTC15m
2026-04-14 SKY557 - Apr 14, 06:45 UTCApr 14, 07:10 UTC25m
2026-04-13 SKY513 - Apr 13, 23:05 UTCApr 13, 23:40 UTC35m
2026-04-13 SKY022 - Apr 13, 10:10 UTCApr 13, 11:30 UTC1h 20m
2026-04-13 SKY021 HND → FUK Apr 13, 08:20 UTCApr 13, 08:50 UTC30m
2026-04-13 SKY021 HND → FUK Apr 13, 07:55 UTCApr 13, 08:50 UTC55m
2026-04-13 SKY021 HND → FUK Apr 13, 07:40 UTCApr 13, 08:15 UTC35m
2026-04-13 SKY012 - Apr 13, 05:15 UTCApr 13, 06:35 UTC1h 20m
2026-04-13 SKY009 - Apr 13, 02:35 UTCApr 13, 03:50 UTC1h 15m
2026-04-13 SKY004 - Apr 13, 00:20 UTCApr 13, 01:20 UTC1h 0m

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 JA73NR page for operator, model, and routing details .

Mode-S 8681B7 frequently asked

What is Mode-S code 8681B7?
8681B7 is an ICAO 24-bit transponder address. Allocated to Japan. Assigned to JA73NR.
Where is Mode-S 8681B7 registered?
Mode-S code 8681B7 is allocated to Japan (JP). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8681B7 broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8681B7, octal 41500667, decimal 8,815,031.
What flights does 8681B7 operate?
Mode-S 8681B7 has broadcast 8 distinct callsigns, including SKY021, SKY520, SKY557, SKY513, SKY022.