sensors Mode-S transponder

781FC4

ICAO 24-bit transponder address · allocated to China

Currently assigned to B-223S · BOEING 777-200LR

Hex
781FC4
Octal
36017704
Decimal
7,872,452
Country
CN
Tail
B-223S
Type
B77L
No current signal · last broadcast 15h ago
Flights observed
6
Distinct callsigns
3
Country
CN
Last broadcast
15h ago

Last known position

Most recent position reported by Mode-S 781FC4.

Country allocation

The ICAO 24-bit address 781FC4 falls within the block assigned to China (CN) by ICAO Annex 10, Volume III. Every aircraft registered in China 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 3 distinct

Callsign Airline Flights Last seen
CAO3124 - 3 2026-04-13
CAO1051 Air China Cargo 2 2026-04-14
CAO3123 - 1 2026-04-12

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-14 CAO1051 PVG → ORD Apr 14, 07:55 UTCApr 14, 09:00 UTC1h 5m
2026-04-13 CAO1051 - Apr 13, 22:55 UTCApr 13, 23:40 UTC45m
2026-04-13 CAO3124 - Apr 13, 11:30 UTCApr 13, 12:00 UTC30m
2026-04-13 CAO3124 - Apr 13, 07:55 UTCApr 13, 11:50 UTC3h 55m
2026-04-13 CAO3124 - Apr 13, 04:30 UTCApr 13, 08:10 UTC3h 40m
2026-04-12 CAO3123 - Apr 12, 18:10 UTCApr 12, 20:05 UTC1h 55m

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 B-223S page for operator, model, and routing details .

Mode-S 781FC4 frequently asked

What is Mode-S code 781FC4?
781FC4 is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-223S.
Where is Mode-S 781FC4 registered?
Mode-S code 781FC4 is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 781FC4 broadcasting right now?
No active broadcast right now. Last signal was 15h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 781FC4, octal 36017704, decimal 7,872,452.
What flights does 781FC4 operate?
Mode-S 781FC4 has broadcast 3 distinct callsigns, including CAO3124, CAO1051, CAO3123.