Apparatus

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sensors Mode-S transponder

8681B5

ICAO 24-bit transponder address · allocated to Japan

Currently assigned to JA73NP · BOEING 737-800

Hex
8681B5
Octal
41500665
Decimal
8,815,029
Country
JP
Tail
JA73NP
Type
B738
No current signal · last broadcast Jul 26, 13:20 UTC
Flights observed
457
Distinct callsigns
20
Country
JP
Last broadcast
Jul 26, 13:20 UTC

Last known position

Most recent position reported by Mode-S 8681B5.

Country allocation

The ICAO 24-bit address 8681B5 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 20 distinct

Callsign Airline Flights Last seen
SKY591 Skymark Airlines 10 2026-06-08
SKY511 - 10 2026-07-14
SKY718 - 9 2026-07-15
SKY597 Skymark Airlines 9 2026-06-10
SKY177 - 9 2026-07-15
SKY618 Skymark Airlines 8 2026-06-09
SKY523 - 7 2026-06-24
SKY521 - 7 2026-06-22
SKY729 Skymark Airlines 6 2026-06-09
SKY706 Skymark Airlines 6 2026-06-09
SKY613 Skymark Airlines 6 2026-06-10
SKY503 Skymark Airlines 6 2026-06-09
SKY185 - 6 2026-06-24
SKY184 - 6 2026-06-24
SKY171 - 6 2026-06-23
SKY170 - 6 2026-06-24
SKY112 - 6 2026-06-24
SKY795 - 5 2026-06-23
SKY794 - 5 2026-06-17
SKY765 - 5 2026-06-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKY726 CTS → HND Jul 26, 11:45 UTCJul 26, 13:15 UTC1h 30m
2026-07-26 SKY723 HND → CTS Jul 26, 08:45 UTCJul 26, 10:00 UTC1h 15m
2026-07-26 SKY518 OKA → HND Jul 26, 05:25 UTCJul 26, 07:35 UTC2h 11m
2026-07-26 SKY501 FUK → OKA Jul 26, 00:20 UTCJul 26, 00:35 UTC15m
2026-07-25 SKY501 FUK → OKA Jul 25, 23:25 UTCJul 25, 23:35 UTC10m
2026-07-25 SKY508 OKA → FUK Jul 25, 11:40 UTCJul 25, 11:55 UTC15m
2026-07-25 SKY508 OKA → FUK Jul 25, 10:45 UTCJul 25, 11:05 UTC20m
2026-07-25 SKY509 FUK → OKA Jul 25, 09:30 UTCJul 25, 09:40 UTC10m
2026-07-25 SKY509 FUK → OKA Jul 25, 08:35 UTCJul 25, 08:45 UTC10m
2026-07-25 SKY506 OKA → FUK Jul 25, 06:00 UTCJul 25, 07:15 UTC1h 15m
2026-07-25 SKY593 UKB → OKA Jul 25, 04:30 UTCJul 25, 04:40 UTC10m
2026-07-25 SKY593 UKB → OKA Jul 25, 03:05 UTCJul 25, 03:45 UTC40m
2026-07-25 SKY153 SDJ → UKB Jul 25, 01:05 UTCJul 25, 02:05 UTC1h 0m
2026-07-24 SKY152 UKB → SDJ Jul 24, 23:00 UTCJul 24, 23:50 UTC50m
2026-07-24 SKY117 HND → UKB Jul 24, 12:25 UTCJul 24, 13:10 UTC45m
2026-07-24 SKY020 FUK → HND Jul 24, 10:05 UTCJul 24, 11:35 UTC1h 30m
2026-07-24 SKY019 HND → FUK Jul 24, 06:30 UTCJul 24, 07:50 UTC1h 20m
2026-07-24 SKY712 CTS → HND Jul 24, 03:10 UTCJul 24, 04:25 UTC1h 15m
2026-07-24 SKY175 UKB → CTS Jul 24, 00:30 UTCJul 24, 02:10 UTC1h 40m
2026-07-23 SKY140 NGS → UKB Jul 23, 22:45 UTCJul 23, 23:40 UTC55m
2026-07-23 SKY147 - Jul 23, 10:55 UTCJul 23, 11:45 UTC50m
2026-07-23 SKY113 HND → UKB Jul 23, 09:15 UTCJul 23, 10:05 UTC50m
2026-07-23 SKY014 FUK → HND Jul 23, 06:00 UTCJul 23, 07:25 UTC1h 25m
2026-07-23 SKY011 HND → FUK Jul 23, 03:05 UTCJul 23, 04:10 UTC1h 5m
2026-07-23 SKY302 KOJ → HND Jul 23, 00:40 UTCJul 23, 01:55 UTC1h 15m
2026-07-22 SKY635 - Jul 22, 21:50 UTCJul 22, 22:30 UTC40m
2026-07-22 SKY638 KOJ → NGO Jul 22, 12:45 UTCJul 22, 13:20 UTC35m
2026-07-22 SKY015 HND → FUK Jul 22, 05:00 UTCJul 22, 11:30 UTC6h 30m
2026-07-22 SKY304 KOJ → HND Jul 22, 02:35 UTCJul 22, 04:00 UTC1h 25m
2026-07-22 SKY303 HND → KOJ Jul 22, 00:05 UTCJul 22, 01:10 UTC1h 5m
2026-07-21 SKY302 - Jul 21, 00:40 UTCJul 21, 01:50 UTC1h 10m
2026-07-20 SKY635 - Jul 20, 21:50 UTCJul 20, 22:25 UTC35m
2026-07-20 SKY638 KOJ → NGO Jul 20, 12:55 UTCJul 20, 13:30 UTC35m
2026-07-20 SKY309 HND → KOJ Jul 20, 10:15 UTCJul 20, 11:15 UTC1h 0m
2026-07-20 SKY018 - Jul 20, 07:45 UTCJul 20, 09:10 UTC1h 25m
2026-07-20 SKY015 - Jul 20, 05:00 UTCJul 20, 06:00 UTC1h 0m
2026-07-20 SKY304 - Jul 20, 02:40 UTCJul 20, 03:55 UTC1h 15m
2026-07-20 SKY303 HND → KOJ Jul 20, 00:05 UTCJul 20, 01:05 UTC1h 0m
2026-07-19 SKY022 - Jul 19, 10:00 UTCJul 19, 11:20 UTC1h 20m
2026-07-19 SKY021 HND → FUK Jul 19, 07:25 UTCJul 19, 08:30 UTC1h 5m
2026-07-18 SKY300 - Jul 18, 11:40 UTCJul 18, 23:45 UTC12h 5m
2026-07-18 SKY176 - Jul 18, 09:20 UTCJul 18, 10:55 UTC1h 35m
2026-07-18 SKY775 FUK → CTS Jul 18, 06:05 UTCJul 18, 08:15 UTC2h 10m
2026-07-18 SKY772 - Jul 18, 02:09 UTCJul 18, 03:50 UTC1h 41m
2026-07-18 SKY791 IBR → CTS Jul 18, 00:04 UTCJul 18, 01:15 UTC1h 10m
2026-07-17 SKY836 - Jul 17, 10:00 UTCJul 17, 11:35 UTC1h 35m
2026-07-17 SKY564 - Jul 17, 04:54 UTCJul 17, 08:49 UTC3h 55m
2026-07-17 SKY563 - Jul 17, 04:10 UTCJul 17, 04:20 UTC10m
2026-07-17 SKY831 - Jul 17, 01:15 UTCJul 17, 02:25 UTC1h 10m
2026-07-16 SKY182 - Jul 16, 23:20 UTCJul 17, 00:20 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 JA73NP page for operator, model, and routing details .

Mode-S 8681B5 frequently asked

What is Mode-S code 8681B5?
8681B5 is an ICAO 24-bit transponder address. Allocated to Japan. Assigned to JA73NP.
Where is Mode-S 8681B5 registered?
Mode-S code 8681B5 is allocated to Japan (JP). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 8681B5 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 13:20 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 8681B5, octal 41500665, decimal 8,815,029.
What flights does 8681B5 operate?
Mode-S 8681B5 has broadcast 20 distinct callsigns, including SKY591, SKY511, SKY718, SKY597, SKY177.