Apparatus

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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 Jul 26, 12:45 UTC
Flights observed
587
Distinct callsigns
20
Country
JP
Last broadcast
Jul 26, 12:45 UTC

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 - 7 2026-06-21
JAL669 - 6 2026-06-21
JAL574 - 6 2026-07-12
JAL565 Japan Airlines 6 2026-07-25
JAL486 Japan Airlines 6 2026-06-07
JAL485 Japan Airlines 6 2026-06-07
JAL476 - 6 2026-06-21
JAL436 - 6 2026-06-21
JAL435 - 6 2026-06-21
JAL668 Japan Airlines 5 2026-06-07
JAL663 Japan Airlines 5 2026-06-07
JAL614 - 5 2026-07-13
JAL611 - 5 2026-07-13
JAL577 - 5 2026-07-12
JAL562 Japan Airlines 5 2026-07-26
JAL490 - 5 2026-07-12
JAL475 - 5 2026-06-20
JAL440 - 5 2026-06-18
JAL439 - 5 2026-06-18
JAL263 Japan Airlines 5 2026-06-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 JAL498 KCZ → HND Jul 26, 12:00 UTCJul 26, 12:45 UTC45m
2026-07-26 JAL497 HND → KCZ Jul 26, 09:50 UTCJul 26, 10:30 UTC40m
2026-07-26 JAL670 OIT → HND Jul 26, 07:05 UTCJul 26, 08:15 UTC1h 10m
2026-07-26 JAL665 HND → OIT Jul 26, 03:30 UTCJul 26, 04:30 UTC1h 0m
2026-07-26 JAL562 MMB → HND Jul 26, 00:45 UTCJul 26, 02:15 UTC1h 30m
2026-07-25 JAL565 HND → MMB Jul 25, 22:30 UTCJul 25, 23:55 UTC1h 25m
2026-07-25 JAL698 KMI → HND Jul 25, 10:35 UTCJul 25, 11:40 UTC1h 5m
2026-07-25 JAL695 HND → KMI Jul 25, 08:10 UTCJul 25, 09:05 UTC55m
2026-07-25 JAL630 KMJ → HND Jul 25, 05:15 UTCJul 25, 06:35 UTC1h 20m
2026-07-25 JAL629 HND → KMJ Jul 25, 02:55 UTCJul 25, 04:10 UTC1h 15m
2026-07-25 JAL642 KOJ → HND Jul 25, 00:35 UTCJul 25, 01:45 UTC1h 10m
2026-07-24 JAL641 HND → KOJ Jul 24, 21:55 UTCJul 24, 23:00 UTC1h 5m
2026-07-23 JAL544 - Jul 23, 11:20 UTCJul 23, 12:35 UTC1h 15m
2026-07-23 JAL545 HND → KUH Jul 23, 08:55 UTCJul 23, 10:10 UTC1h 15m
2026-07-23 JAL146 AOJ → HND Jul 23, 06:35 UTCJul 23, 07:25 UTC50m
2026-07-23 JAL145 HND → AOJ Jul 23, 04:45 UTCJul 23, 05:35 UTC50m
2026-07-23 JAL374 KKJ → HND Jul 23, 01:55 UTCJul 23, 03:10 UTC1h 15m
2026-07-22 JAL373C - Jul 22, 23:40 UTCJul 23, 00:45 UTC1h 5m
2026-07-22 JAL566 - Jul 22, 11:10 UTCJul 22, 12:50 UTC1h 40m
2026-07-22 JAL659 HND → ASJ Jul 22, 02:55 UTCJul 22, 03:35 UTC40m
2026-07-22 JAL212 SHM → HND Jul 22, 01:00 UTCJul 22, 01:45 UTC45m
2026-07-21 JAL213 HND → SHM Jul 21, 23:10 UTCJul 21, 23:45 UTC35m
2026-07-21 JAL192 KMQ → HND Jul 21, 12:00 UTCJul 21, 12:50 UTC50m
2026-07-21 JAL191 - Jul 21, 10:30 UTCJul 21, 11:10 UTC40m
2026-07-21 JAL982 OKA → HND Jul 21, 07:10 UTCJul 21, 09:20 UTC2h 10m
2026-07-21 JAL981 HND → UEO Jul 21, 02:25 UTCJul 21, 04:30 UTC2h 5m
2026-07-21 JAL184 KMQ → HND Jul 21, 00:00 UTCJul 21, 00:55 UTC55m
2026-07-20 JAL183 HND → KMQ Jul 20, 22:30 UTCJul 20, 23:10 UTC40m
2026-07-20 JAL378 KKJ → HND Jul 20, 12:15 UTCJul 20, 13:30 UTC1h 15m
2026-07-20 JAL377 - Jul 20, 09:45 UTCJul 20, 10:50 UTC1h 5m
2026-07-20 JAL496 - Jul 20, 07:35 UTCJul 20, 08:40 UTC1h 5m
2026-07-20 JAL495 HND → KCZ Jul 20, 05:25 UTCJul 20, 06:05 UTC40m
2026-07-20 JAL144 AOJ → HND Jul 20, 03:20 UTCJul 20, 04:25 UTC1h 5m
2026-07-20 JAL143 - Jul 20, 01:25 UTCJul 20, 02:15 UTC50m
2026-07-19 JAL606 NGS → HND Jul 19, 22:35 UTCJul 20, 00:00 UTC1h 25m
2026-07-19 JAL615V - Jul 19, 10:50 UTCJul 19, 12:10 UTC1h 20m
2026-07-19 JAL484 - Jul 19, 08:40 UTCJul 19, 09:50 UTC1h 10m
2026-07-19 JAL483 - Jul 19, 06:30 UTCJul 19, 07:20 UTC50m
2026-07-19 JAL610 NGS → HND Jul 19, 03:55 UTCJul 19, 05:20 UTC1h 25m
2026-07-19 JAL607 - Jul 19, 01:35 UTCJul 19, 02:55 UTC1h 20m
2026-07-18 JAL590 CTS → HND Jul 18, 22:45 UTCJul 19, 00:00 UTC1h 15m
2026-07-18 JAL599 - Jul 18, 12:00 UTCJul 18, 13:20 UTC1h 20m
2026-07-18 JAL264 - Jul 18, 09:10 UTCJul 18, 10:15 UTC1h 5m
2026-07-18 JAL3406 - Jul 18, 06:20 UTCJul 18, 08:05 UTC1h 45m
2026-07-18 JAL3513 - Jul 18, 03:05 UTCJul 18, 05:05 UTC2h 0m
2026-07-18 JAL309 - Jul 18, 00:25 UTCJul 18, 01:30 UTC1h 5m
2026-07-17 JAL452 - Jul 17, 22:15 UTCJul 17, 23:10 UTC55m
2026-07-17 JAL465 - Jul 17, 11:25 UTCJul 17, 12:15 UTC50m
2026-07-17 JAL520 - Jul 17, 08:59 UTCJul 17, 10:15 UTC1h 15m
2026-07-17 JAL3515 - Jul 17, 05:39 UTCJul 17, 07:44 UTC2h 5m

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 Jul 26, 12:45 UTC.
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, JAL669, JAL574, JAL565, JAL486.