sensors Mode-S transponder

7801AD

ICAO 24-bit transponder address · allocated to China

Currently assigned to B-HYJ · AIRBUS A-330-300

Hex
7801AD
Octal
36000655
Decimal
7,864,749
Country
CN
Tail
B-HYJ
Type
A333
No current signal · last broadcast 15h ago
Flights observed
6
Distinct callsigns
5
Country
CN
Last broadcast
15h ago

Last known position

Most recent position reported by Mode-S 7801AD.

Country allocation

The ICAO 24-bit address 7801AD 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 5 distinct

Callsign Airline Flights Last seen
CPA495 Cathay Pacific 2 2026-04-14
CPA912 Cathay Pacific 1 2026-04-13
CPA393 - 1 2026-04-13
CPA392 - 1 2026-04-13
CPA364 - 1 2026-04-14

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-14 CPA364 - Apr 14, 09:50 UTCApr 14, 11:00 UTC1h 10m
2026-04-14 CPA495 TPE → HKG Apr 14, 06:30 UTCApr 14, 06:50 UTC20m
2026-04-14 CPA495 TPE → HKG Apr 14, 05:25 UTCApr 14, 05:55 UTC30m
2026-04-13 CPA393 - Apr 13, 13:55 UTCApr 13, 14:25 UTC30m
2026-04-13 CPA392 - Apr 13, 06:45 UTCApr 13, 07:05 UTC20m
2026-04-13 CPA912 MNL → HKG Apr 13, 00:35 UTCApr 13, 02:10 UTC1h 35m

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-HYJ page for operator, model, and routing details .

Mode-S 7801AD frequently asked

What is Mode-S code 7801AD?
7801AD is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-HYJ.
Where is Mode-S 7801AD registered?
Mode-S code 7801AD is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 7801AD 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 7801AD, octal 36000655, decimal 7,864,749.
What flights does 7801AD operate?
Mode-S 7801AD has broadcast 5 distinct callsigns, including CPA495, CPA912, CPA393, CPA392, CPA364.