sensors Mode-S transponder

851F4E

ICAO 24-bit transponder address · allocated to Japan

Currently assigned to JA350J · BOEING 737-800

Hex
851F4E
Octal
41217516
Decimal
8,724,302
Country
JP
Tail
JA350J
Type
B738
Broadcasting now · callsign JTA121 · 33,475 ft
Flights observed
5
Distinct callsigns
4
Country
JP
Last broadcast
15h ago

Current position

851F4E is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 851F4E 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 4 distinct

Callsign Airline Flights Last seen
JTA37 - 2 2026-04-14
JTA83 - 1 2026-04-13
JTA564 Japan Transocean Air 1 2026-04-13
JTA16 - 1 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-14 JTA37 - Apr 14, 07:30 UTCApr 14, 07:45 UTC15m
2026-04-14 JTA37 - Apr 14, 05:50 UTCApr 14, 06:25 UTC35m
2026-04-13 JTA16 - Apr 13, 10:00 UTCApr 13, 10:20 UTC20m
2026-04-13 JTA564 MMY → OKA Apr 13, 08:35 UTCApr 13, 08:45 UTC10m
2026-04-13 JTA83 - Apr 13, 01:20 UTCApr 13, 03:00 UTC1h 40m

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 JA350J page for operator, model, and routing details .

Mode-S 851F4E frequently asked

What is Mode-S code 851F4E?
851F4E is an ICAO 24-bit transponder address. Allocated to Japan. Assigned to JA350J.
Where is Mode-S 851F4E registered?
Mode-S code 851F4E is allocated to Japan (JP). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 851F4E broadcasting right now?
Yes. Mode-S 851F4E is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 851F4E, octal 41217516, decimal 8,724,302.
What flights does 851F4E operate?
Mode-S 851F4E has broadcast 4 distinct callsigns, including JTA37, JTA83, JTA564, JTA16.