Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

851C20

ICAO 24-bit transponder address · allocated to Japan

Currently assigned to JA343J · BOEING 737-800

Hex
851C20
Octal
41216040
Decimal
8,723,488
Country
JP
Tail
JA343J
Type
B738
No current signal · last broadcast 2h ago
Flights observed
299
Distinct callsigns
20
Country
JP
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 851C20.

Country allocation

The ICAO 24-bit address 851C20 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
JAL214 Japan Airlines 9 2026-05-26
JAL432 Japan Airlines 7 2026-05-26
JAL509 Japan Airlines 6 2026-05-23
JAL461 Japan Airlines 6 2026-05-22
JAL431 Japan Airlines 6 2026-05-25
JAL2506 Japan Airlines 6 2026-05-23
JAL228 Japan Airlines 6 2026-05-23
JAL2009 Japan Airlines 6 2026-05-23
JAL2004 Japan Airlines 6 2026-05-23
JAL151 Japan Airlines 6 2026-05-22
JAL140 Japan Airlines 6 2026-05-22
JAL462 Japan Airlines 5 2026-05-22
JAL215 Japan Airlines 5 2026-05-26
JAL671 Japan Airlines 4 2026-05-26
JAL662 Japan Airlines 4 2026-05-26
JAL624 Japan Airlines 4 2026-05-17
JAL623 Japan Airlines 4 2026-05-16
JAL148 Japan Airlines 4 2026-05-26
JAL147 Japan Airlines 4 2026-05-26
JAL658 Japan Airlines 3 2026-05-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 JAL193 HND → KMQ May 30, 12:00 UTCMay 30, 12:45 UTC45m
2026-05-30 JAL190 KMQ → HND May 30, 09:55 UTCMay 30, 10:55 UTC1h 0m
2026-05-30 JAL189 HND → KIX May 30, 08:20 UTCMay 30, 09:05 UTC45m
2026-05-30 JAL188 KMQ → HND May 30, 06:10 UTCMay 30, 07:05 UTC55m
2026-05-30 JAL187 HND → KMQ May 30, 04:40 UTCMay 30, 05:20 UTC40m
2026-05-30 JAL690 KMI → HND May 30, 02:00 UTCMay 30, 03:05 UTC1h 5m
2026-05-29 JAL687 HND → KMI May 29, 23:35 UTCMay 30, 00:35 UTC1h 0m
2026-05-29 JAL544 KUH → HND May 29, 11:40 UTCMay 29, 13:10 UTC1h 30m
2026-05-29 JAL545 HND → KUH May 29, 09:15 UTCMay 29, 10:15 UTC1h 0m
2026-05-29 JAL648 KOJ → HND May 29, 06:55 UTCMay 29, 07:55 UTC1h 0m
2026-05-29 JAL647 HND → KOJ May 29, 04:00 UTCMay 29, 05:10 UTC1h 10m
2026-05-29 JAL492 KCZ → HND May 29, 01:10 UTCMay 29, 02:00 UTC50m
2026-05-28 JAL491 HND → KCZ May 28, 22:55 UTCMay 28, 23:40 UTC45m
2026-05-28 JAL134 ITM → HND May 28, 11:45 UTCMay 28, 12:35 UTC50m
2026-05-28 JAL131 HND → ITM May 28, 09:20 UTCMay 28, 10:05 UTC45m
2026-05-28 JAL482 TAK → HND May 28, 06:40 UTCMay 28, 08:00 UTC1h 20m
2026-05-28 JAL481 HND → TAK May 28, 04:30 UTCMay 28, 05:25 UTC55m
2026-05-28 JAL186 KIX → HND May 28, 02:30 UTCMay 28, 03:25 UTC55m
2026-05-28 JAL185 HND → KMQ May 28, 00:55 UTCMay 28, 01:35 UTC40m
2026-05-27 JAL232 OKJ → HND May 27, 22:25 UTCMay 27, 23:35 UTC1h 10m
2026-05-27 JAL241 HND → OKJ May 27, 10:55 UTCMay 27, 11:45 UTC50m
2026-05-27 JAL240 OKJ → HND May 27, 08:55 UTCMay 27, 09:50 UTC55m
2026-05-27 JAL237 HND → OKJ May 27, 05:55 UTCMay 27, 06:44 UTC50m
2026-05-27 JAL236 OKJ → HND May 27, 03:34 UTCMay 27, 04:30 UTC55m
2026-05-27 JAL233 HND → OKJ May 27, 01:44 UTCMay 27, 02:39 UTC55m
2026-05-26 JAL662 OIT → HND May 26, 22:54 UTCMay 26, 23:54 UTC1h 0m
2026-05-26 JAL671 HND → OIT May 26, 11:24 UTCMay 26, 12:30 UTC1h 5m
2026-05-26 JAL148 AOJ → HND May 26, 09:04 UTCMay 26, 10:05 UTC1h 0m
2026-05-26 JAL147 HND → AOJ May 26, 07:24 UTCMay 26, 08:15 UTC50m
2026-05-26 JAL214 SHM → HND May 26, 05:10 UTCMay 26, 05:45 UTC35m
2026-05-26 JAL215 HND → SHM May 26, 02:44 UTCMay 26, 03:19 UTC35m
2026-05-26 JAL432 MYJ → HND May 26, 00:29 UTCMay 26, 01:34 UTC1h 5m
2026-05-25 JAL431 HND → MYJ May 25, 22:05 UTCMay 25, 23:10 UTC1h 5m
2026-05-25 JAL654 KOJ → HND May 25, 12:35 UTCMay 25, 13:40 UTC1h 5m
2026-05-25 JAL653 HND → KOJ May 25, 09:55 UTCMay 25, 11:00 UTC1h 5m
2026-05-25 JAL612 NGS → HND May 25, 06:40 UTCMay 25, 08:10 UTC1h 30m
2026-05-25 JAL609 HND → NGS May 25, 03:50 UTCMay 25, 05:10 UTC1h 20m
2026-05-24 JAL608 NGS → HND May 24, 23:00 UTCMay 25, 02:45 UTC3h 45m
2026-05-24 JAL558 AKJ → HND May 24, 11:25 UTCMay 24, 12:45 UTC1h 20m
2026-05-24 JAL557 HND → AKJ May 24, 09:10 UTCMay 24, 10:20 UTC1h 10m
2026-05-24 JAL658 ASJ → HND May 24, 03:10 UTCMay 24, 07:45 UTC4h 35m
2026-05-23 JAL641 HND → KOJ May 23, 21:45 UTCMay 24, 01:30 UTC3h 45m
2026-05-23 JAL228 KIX → HND May 23, 12:40 UTCMay 23, 13:30 UTC50m
2026-05-23 JAL2506 CTS → KIX May 23, 09:05 UTCMay 23, 11:00 UTC1h 55m
2026-05-23 JAL2009 ITM → CTS May 23, 06:30 UTCMay 23, 08:05 UTC1h 35m
2026-05-23 JAL2004 CTS → ITM May 23, 03:20 UTCMay 23, 05:00 UTC1h 40m
2026-05-23 JAL509 HND → CTS May 23, 01:10 UTCMay 23, 02:20 UTC1h 10m
2026-05-22 JAL140 AOJ → HND May 22, 22:50 UTCMay 22, 23:40 UTC50m
2026-05-22 JAL151 HND → AOJ May 22, 11:15 UTCMay 22, 12:05 UTC50m
2026-05-22 JAL462 TKS → HND May 22, 08:50 UTCMay 22, 10:00 UTC1h 10m

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 JA343J page for operator, model, and routing details .

Mode-S 851C20 frequently asked

What is Mode-S code 851C20?
851C20 is an ICAO 24-bit transponder address. Allocated to Japan. Assigned to JA343J.
Where is Mode-S 851C20 registered?
Mode-S code 851C20 is allocated to Japan (JP). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 851C20 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 851C20, octal 41216040, decimal 8,723,488.
What flights does 851C20 operate?
Mode-S 851C20 has broadcast 20 distinct callsigns, including JAL214, JAL432, JAL509, JAL461, JAL431.