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
Transponder active on ground
Flights observed
617
Distinct callsigns
20
Country
JP
Last broadcast
Jul 26, 14:10 UTC

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 - 11 2026-06-23
JAL509 - 8 2026-06-20
JAL461 Japan Airlines 8 2026-06-07
JAL2506 Japan Airlines 8 2026-07-25
JAL228 Japan Airlines 8 2026-07-25
JAL2004 - 8 2026-06-20
JAL151 - 8 2026-06-19
JAL140 - 8 2026-06-19
JAL462 Japan Airlines 7 2026-06-07
JAL432 Japan Airlines 7 2026-05-26
JAL215 - 7 2026-06-23
JAL2009 - 7 2026-06-17
JAL641 - 6 2026-07-01
JAL562 - 6 2026-07-19
JAL431 Japan Airlines 6 2026-05-25
JAL671 - 5 2026-06-23
JAL662 - 5 2026-06-23
JAL624 Japan Airlines 5 2026-06-07
JAL623 Japan Airlines 5 2026-06-06
JAL609 - 5 2026-07-13

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 JAL566 MMB → HND Jul 26, 12:25 UTCJul 26, 13:55 UTC1h 30m
2026-07-26 JAL569 HND → MMB Jul 26, 10:10 UTCJul 26, 11:30 UTC1h 20m
2026-07-26 JAL542 KUH → HND Jul 26, 07:40 UTCJul 26, 09:00 UTC1h 20m
2026-07-26 JAL543 HND → KUH Jul 26, 03:40 UTCJul 26, 04:45 UTC1h 5m
2026-07-26 JAL112 ITM → HND Jul 26, 01:40 UTCJul 26, 02:30 UTC50m
2026-07-25 JAL107 HND → ITM Jul 25, 23:50 UTCJul 26, 00:35 UTC45m
2026-07-25 JAL228 KIX → HND Jul 25, 12:30 UTCJul 25, 13:20 UTC50m
2026-07-25 JAL2506 CTS → KIX Jul 25, 09:20 UTCJul 25, 11:00 UTC1h 40m
2026-07-25 JAL2505 KIX → CTS Jul 25, 06:30 UTCJul 25, 08:05 UTC1h 35m
2026-07-25 JAL2504 CTS → KIX Jul 25, 03:10 UTCJul 25, 05:05 UTC1h 55m
2026-07-25 JAL2501 KIX → CTS Jul 25, 00:40 UTCJul 25, 02:10 UTC1h 30m
2026-07-24 JAL221 HND → KIX Jul 24, 22:40 UTCJul 24, 23:30 UTC50m
2026-07-24 JAL378 KKJ → HND Jul 24, 12:35 UTCJul 24, 14:00 UTC1h 25m
2026-07-24 JAL377 HND → KKJ Jul 24, 10:25 UTCJul 24, 11:25 UTC1h 0m
2026-07-24 JAL496 KCZ → HND Jul 24, 07:55 UTCJul 24, 09:05 UTC1h 10m
2026-07-24 JAL495 HND → KCZ Jul 24, 05:25 UTCJul 24, 06:05 UTC40m
2026-07-24 JAL144 AOJ → HND Jul 24, 03:20 UTCJul 24, 04:15 UTC55m
2026-07-24 JAL143 HND → AOJ Jul 24, 01:25 UTCJul 24, 02:20 UTC55m
2026-07-23 JAL606 NGS → HND Jul 23, 22:40 UTCJul 24, 00:15 UTC1h 35m
2026-07-23 JAL615V - Jul 23, 11:20 UTCJul 23, 12:45 UTC1h 25m
2026-07-23 JAL484 TAK → HND Jul 23, 08:50 UTCJul 23, 10:00 UTC1h 10m
2026-07-23 JAL483 HND → TAK Jul 23, 06:55 UTCJul 23, 07:45 UTC50m
2026-07-23 JAL480 TAK → HND Jul 23, 04:35 UTCJul 23, 05:35 UTC1h 0m
2026-07-23 JAL479 HND → TAK Jul 23, 02:50 UTCJul 23, 03:40 UTC50m
2026-07-23 JAL278 IZO → HND Jul 23, 00:40 UTCJul 23, 01:40 UTC1h 0m
2026-07-22 JAL277 HND → IZO Jul 22, 22:30 UTCJul 22, 23:20 UTC50m
2026-07-22 JAL168 AXT → HND Jul 22, 13:25 UTCJul 22, 14:20 UTC55m
2026-07-22 JAL167 HND → AXT Jul 22, 11:35 UTCJul 22, 12:05 UTC30m
2026-07-22 JAL3513 FUK → CTS Jul 22, 03:15 UTCJul 22, 05:05 UTC1h 50m
2026-07-22 JAL309 HND → FUK Jul 22, 00:25 UTCJul 22, 01:35 UTC1h 10m
2026-07-21 JAL452 TKS → HND Jul 21, 22:15 UTCJul 21, 23:10 UTC55m
2026-07-21 JAL465 HND → TKS Jul 21, 11:10 UTCJul 21, 12:00 UTC50m
2026-07-21 JAL520 - Jul 21, 08:45 UTCJul 21, 10:10 UTC1h 25m
2026-07-21 JAL3515 FUK → CTS Jul 21, 05:40 UTCJul 21, 07:40 UTC2h 0m
2026-07-21 JAL3510 CTS → FUK Jul 21, 01:55 UTCJul 21, 03:40 UTC1h 45m
2026-07-20 JAL3101 NGO → CTS Jul 20, 23:25 UTCJul 21, 00:40 UTC1h 14m
2026-07-20 JAL209 - Jul 20, 11:30 UTCJul 20, 12:00 UTC30m
2026-07-20 JAL438 MYJ → HND Jul 20, 09:00 UTCJul 20, 10:15 UTC1h 15m
2026-07-20 JAL437 HND → MYJ Jul 20, 06:55 UTCJul 20, 07:55 UTC1h 0m
2026-07-20 JAL480 TAK → HND Jul 20, 04:30 UTCJul 20, 05:30 UTC1h 0m
2026-07-20 JAL479 - Jul 20, 02:35 UTCJul 20, 03:25 UTC50m
2026-07-20 JAL278 IZO → HND Jul 20, 00:25 UTCJul 20, 01:25 UTC1h 0m
2026-07-19 JAL277 HND → IZO Jul 19, 22:25 UTCJul 19, 23:10 UTC45m
2026-07-19 JAL674 - Jul 19, 10:35 UTCJul 19, 11:45 UTC1h 10m
2026-07-19 JAL669 - Jul 19, 08:20 UTCJul 19, 09:25 UTC1h 5m
2026-07-19 JAL670 - Jul 19, 05:45 UTCJul 19, 07:00 UTC1h 15m
2026-07-19 JAL665 HND → OIT Jul 19, 03:30 UTCJul 19, 04:30 UTC1h 0m
2026-07-19 JAL562 - Jul 19, 00:35 UTCJul 19, 02:10 UTC1h 35m
2026-07-18 JAL565 HND → MMB Jul 18, 22:20 UTCJul 18, 23:45 UTC1h 25m
2026-07-18 JAL376 - Jul 18, 07:30 UTCJul 18, 08:50 UTC1h 20m

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?
Mode-S 851C20 is currently broadcasting from the ground.
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, JAL509, JAL461, JAL2506, JAL228.