Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

851C42

ICAO 24-bit transponder address · allocated to Japan

Currently assigned to JA344J · BOEING 737-800

Hex
851C42
Octal
41216102
Decimal
8,723,522
Country
JP
Tail
JA344J
Type
B738
No current signal · last broadcast 3h ago
Flights observed
278
Distinct callsigns
20
Country
JP
Last broadcast
3h ago

Last known position

Most recent position reported by Mode-S 851C42.

Country allocation

The ICAO 24-bit address 851C42 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
JAL674 Japan Airlines 5 2026-05-18
JAL565 Japan Airlines 5 2026-05-24
JAL669 Japan Airlines 4 2026-05-18
JAL562 Japan Airlines 4 2026-05-19
JAL486 Japan Airlines 4 2026-05-26
JAL485 Japan Airlines 4 2026-05-26
JAL476 Japan Airlines 4 2026-05-18
JAL436 Japan Airlines 4 2026-05-18
JAL435 Japan Airlines 4 2026-05-18
JAL668 Japan Airlines 3 2026-05-26
JAL665 Japan Airlines 3 2026-05-25
JAL664 Japan Airlines 3 2026-05-28
JAL663 Japan Airlines 3 2026-05-26
JAL661 Japan Airlines 3 2026-05-27
JAL632 Japan Airlines 3 2026-05-24
JAL631 Japan Airlines 3 2026-05-24
JAL574 Japan Airlines 3 2026-04-20
JAL478 Japan Airlines 3 2026-04-20
JAL475 Japan Airlines 3 2026-05-17
JAL440 Japan Airlines 3 2026-05-30

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 JAL440 MYJ → HND May 30, 10:20 UTCMay 30, 11:25 UTC1h 5m
2026-05-30 JAL439 HND → MYJ May 30, 08:10 UTCMay 30, 09:20 UTC1h 10m
2026-05-30 JAL224 KIX → HND May 30, 06:05 UTCMay 30, 06:55 UTC50m
2026-05-30 JAL225 HND → KIX May 30, 03:50 UTCMay 30, 04:45 UTC55m
2026-05-30 JAL540 KUH → HND May 30, 01:20 UTCMay 30, 02:45 UTC1h 25m
2026-05-29 JAL541 HND → KUH May 29, 23:10 UTCMay 30, 00:05 UTC55m
2026-05-28 JAL558 AKJ → HND May 28, 11:45 UTCMay 28, 14:00 UTC2h 15m
2026-05-28 JAL557 HND → AKJ May 28, 09:15 UTCMay 28, 10:30 UTC1h 15m
2026-05-28 JAL146 AOJ → HND May 28, 06:45 UTCMay 28, 07:45 UTC1h 0m
2026-05-28 JAL145 HND → AOJ May 28, 04:30 UTCMay 28, 05:25 UTC55m
2026-05-28 JAL664 OIT → HND May 28, 01:50 UTCMay 28, 03:00 UTC1h 10m
2026-05-27 JAL661 HND → OIT May 27, 23:25 UTCMay 28, 00:30 UTC1h 5m
2026-05-27 JAL440 MYJ → HND May 27, 10:30 UTCMay 27, 11:45 UTC1h 15m
2026-05-27 JAL439 HND → MYJ May 27, 08:25 UTCMay 27, 09:25 UTC1h 0m
2026-05-27 JAL224 KIX → HND May 27, 06:15 UTCMay 27, 07:15 UTC1h 1m
2026-05-27 JAL225 HND → KIX May 27, 04:14 UTCMay 27, 05:09 UTC55m
2026-05-27 JAL540 KUH → HND May 27, 01:34 UTCMay 27, 02:54 UTC1h 20m
2026-05-26 JAL541 HND → KUH May 26, 23:05 UTCMay 27, 00:14 UTC1h 10m
2026-05-26 JAL486 TAK → HND May 26, 11:50 UTCMay 26, 12:50 UTC1h 0m
2026-05-26 JAL485 HND → TAK May 26, 10:05 UTCMay 26, 10:54 UTC50m
2026-05-26 JAL262 HIJ → HND May 26, 07:40 UTCMay 26, 08:45 UTC1h 5m
2026-05-26 JAL263 HND → HIJ May 26, 05:34 UTCMay 26, 06:39 UTC1h 5m
2026-05-26 JAL668 OIT → HND May 26, 03:05 UTCMay 26, 04:10 UTC1h 5m
2026-05-26 JAL663 HND → OIT May 26, 01:00 UTCMay 26, 02:00 UTC1h 0m
2026-05-25 JAL182 KMQ → HND May 25, 22:49 UTCMay 25, 23:49 UTC1h 0m
2026-05-25 JAL193 HND → KMQ May 25, 12:50 UTCMay 25, 13:25 UTC35m
2026-05-25 JAL190 KMQ → HND May 25, 11:10 UTCMay 25, 11:50 UTC40m
2026-05-25 JAL189 HND → KIX May 25, 08:30 UTCMay 25, 09:05 UTC35m
2026-05-25 JAL670 OIT → HND May 25, 05:45 UTCMay 25, 06:55 UTC1h 10m
2026-05-25 JAL665 HND → OIT May 25, 03:30 UTCMay 25, 04:30 UTC1h 0m
2026-05-25 JAL665 HND → OIT May 25, 01:55 UTCMay 25, 02:05 UTC10m
2026-05-24 JAL565 HND → MMB May 24, 23:20 UTCMay 24, 23:46 UTC26m
2026-05-24 JAL653 HND → KOJ May 24, 09:25 UTCMay 24, 13:10 UTC3h 45m
2026-05-24 JAL632 KMJ → HND May 24, 06:45 UTCMay 24, 08:20 UTC1h 35m
2026-05-24 JAL631 HND → KMJ May 24, 04:25 UTCMay 24, 05:50 UTC1h 25m
2026-05-24 JAL626 KMJ → HND May 24, 01:55 UTCMay 24, 03:15 UTC1h 20m
2026-05-23 JAL625 HND → KMJ May 23, 23:30 UTCMay 24, 00:55 UTC1h 25m
2026-05-23 JAL544 KUH → HND May 23, 11:20 UTCMay 23, 12:35 UTC1h 15m
2026-05-23 JAL545 HND → KUH May 23, 09:00 UTCMay 23, 09:30 UTC30m
2026-05-23 JAL647 HND → KOJ May 23, 03:30 UTCMay 23, 07:25 UTC3h 55m
2026-05-23 JAL492 KCZ → HND May 23, 01:05 UTCMay 23, 01:55 UTC50m
2026-05-22 JAL491 HND → KCZ May 22, 22:45 UTCMay 22, 23:30 UTC45m
2026-05-22 JAL242 OKJ → HND May 22, 10:45 UTCMay 22, 11:40 UTC55m
2026-05-22 JAL239 HND → OKJ May 22, 08:50 UTCMay 22, 09:40 UTC50m
2026-05-22 JAL482 TAK → HND May 22, 06:30 UTCMay 22, 07:35 UTC1h 5m
2026-05-22 JAL481 HND → TAK May 22, 04:30 UTCMay 22, 05:20 UTC50m
2026-05-22 JAL186 KIX → HND May 22, 02:30 UTCMay 22, 03:25 UTC55m
2026-05-22 JAL185 HND → KMQ May 22, 00:50 UTCMay 22, 01:10 UTC20m
2026-05-21 JAL452 TKS → HND May 21, 22:15 UTCMay 21, 23:10 UTC55m
2026-05-21 JAL465 HND → TKS May 21, 11:10 UTCMay 21, 12:10 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 JA344J page for operator, model, and routing details .

Mode-S 851C42 frequently asked

What is Mode-S code 851C42?
851C42 is an ICAO 24-bit transponder address. Allocated to Japan. Assigned to JA344J.
Where is Mode-S 851C42 registered?
Mode-S code 851C42 is allocated to Japan (JP). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 851C42 broadcasting right now?
No active broadcast right now. Last signal was 3h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 851C42, octal 41216102, decimal 8,723,522.
What flights does 851C42 operate?
Mode-S 851C42 has broadcast 20 distinct callsigns, including JAL674, JAL565, JAL669, JAL562, JAL486.