sensors Mode-S transponder

8681B3

ICAO 24-bit transponder address · allocated to Japan

Currently assigned to JA73NM · BOEING 737-800

Hex
8681B3
Octal
41500663
Decimal
8,815,027
Country
JP
Tail
JA73NM
Type
B738
Broadcasting now · callsign SKY101 · 22,800 ft
Flights observed
13
Distinct callsigns
8
Country
JP
Last broadcast
13h ago

Current position

8681B3 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 8681B3 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
SKY713 - 3 2026-04-13
SKY718 Skymark Airlines 2 2026-04-14
SKY522 - 2 2026-04-13
SKY023 - 2 2026-04-14
SKY716 - 1 2026-04-13
SKY521 Skymark Airlines 1 2026-04-13
SKY512 - 1 2026-04-13
SKY511 - 1 2026-04-13

Recent flights last 13

DateFlightRouteTakeoffLandingDuration
2026-04-14 SKY023 - Apr 14, 09:10 UTCApr 14, 10:10 UTC1h 0m
2026-04-14 SKY023 - Apr 14, 08:55 UTCApr 14, 09:05 UTC10m
2026-04-14 SKY718 CTS → HND Apr 14, 07:10 UTCApr 14, 07:40 UTC30m
2026-04-14 SKY718 CTS → HND Apr 14, 06:25 UTCApr 14, 07:10 UTC45m
2026-04-13 SKY511 - Apr 13, 21:55 UTCApr 13, 22:30 UTC35m
2026-04-13 SKY522 - Apr 13, 13:10 UTCApr 13, 13:45 UTC35m
2026-04-13 SKY522 - Apr 13, 11:50 UTCApr 13, 12:05 UTC15m
2026-04-13 SKY521 HND → OKA Apr 13, 08:25 UTCApr 13, 10:40 UTC2h 15m
2026-04-13 SKY716 - Apr 13, 06:00 UTCApr 13, 07:15 UTC1h 15m
2026-04-13 SKY713 - Apr 13, 04:20 UTCApr 13, 04:50 UTC30m
2026-04-13 SKY713 - Apr 13, 03:55 UTCApr 13, 04:50 UTC55m
2026-04-13 SKY713 - Apr 13, 03:40 UTCApr 13, 04:15 UTC35m
2026-04-13 SKY512 - Apr 13, 00:20 UTCApr 13, 02:20 UTC2h 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 JA73NM page for operator, model, and routing details .

Mode-S 8681B3 frequently asked

What is Mode-S code 8681B3?
8681B3 is an ICAO 24-bit transponder address. Allocated to Japan. Assigned to JA73NM.
Where is Mode-S 8681B3 registered?
Mode-S code 8681B3 is allocated to Japan (JP). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8681B3 broadcasting right now?
Yes. Mode-S 8681B3 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8681B3, octal 41500663, decimal 8,815,027.
What flights does 8681B3 operate?
Mode-S 8681B3 has broadcast 8 distinct callsigns, including SKY713, SKY718, SKY522, SKY023, SKY716.