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sensors Mode-S transponder

78921B

ICAO 24-bit transponder address · allocated to China

Currently assigned to B-HNS · BOEING 777-300

Hex
78921B
Octal
36111033
Decimal
7,901,723
Country
CN
Tail
B-HNS
Type
B773
Broadcasting now · callsign CPA451 · 35,975 ft
Flights observed
363
Distinct callsigns
20
Country
CN
Last broadcast
2h ago

Current position

78921B is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 78921B 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 20 distinct

Callsign Airline Flights Last seen
CPA521 - 21 2026-06-15
CPA450 - 17 2026-07-03
CPA565 Cathay Pacific 15 2026-05-31
CPA974 - 14 2026-07-10
CPA918 - 14 2026-07-13
CPA507 - 13 2026-07-06
CPA913 - 12 2026-07-10
CPA785 - 12 2026-07-05
CPA520 - 12 2026-06-15
CPA919 - 11 2026-07-13
CPA798 - 11 2026-07-11
CPA505 - 11 2026-07-03
CPA361 - 11 2026-07-09
CPA451 Cathay Pacific 10 2026-06-09
CPA506 - 9 2026-07-06
CPA362 - 9 2026-06-30
CPA930 - 8 2026-07-07
CPA784 - 8 2026-07-05
CPA564 Cathay Pacific 8 2026-05-31
CPA421 - 8 2026-07-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 CPA504 - Jul 14, 01:45 UTCJul 14, 05:45 UTC4h 0m
2026-07-13 CPA918 - Jul 13, 11:55 UTCJul 13, 12:10 UTC15m
2026-07-13 CPA918 - Jul 13, 10:35 UTCJul 13, 11:00 UTC25m
2026-07-13 CPA919 - Jul 13, 07:40 UTCJul 13, 08:15 UTC35m
2026-07-13 CPA919 - Jul 13, 06:30 UTCJul 13, 06:45 UTC15m
2026-07-13 CPA431 KHH → HKG Jul 13, 03:30 UTCJul 13, 04:30 UTC1h 0m
2026-07-13 CPA432 HKG → KHH Jul 13, 00:55 UTCJul 13, 02:01 UTC1h 5m
2026-07-12 CPA411 ICN → HKG Jul 12, 07:10 UTCJul 12, 10:05 UTC2h 55m
2026-07-12 CPA410 - Jul 12, 03:01 UTCJul 12, 05:15 UTC2h 15m
2026-07-12 CPA410 - Jul 12, 02:10 UTCJul 12, 02:25 UTC15m
2026-07-11 CPA798 - Jul 11, 21:50 UTCJul 11, 22:20 UTC30m
2026-07-11 CPA798 - Jul 11, 17:50 UTCJul 11, 19:15 UTC1h 25m
2026-07-11 CPA797 - Jul 11, 15:35 UTCJul 11, 15:50 UTC15m
2026-07-11 CPA797 - Jul 11, 11:40 UTCJul 11, 11:50 UTC10m
2026-07-11 CPA973 - Jul 11, 07:05 UTCJul 11, 07:15 UTC10m
2026-07-11 CPA970 - Jul 11, 01:55 UTCJul 11, 02:05 UTC10m
2026-07-10 CPA974 - Jul 10, 23:05 UTCJul 10, 23:25 UTC20m
2026-07-10 CPA974 - Jul 10, 21:50 UTCJul 10, 22:20 UTC30m
2026-07-10 CPA913 - Jul 10, 12:55 UTCJul 10, 14:35 UTC1h 40m
2026-07-10 CPA421 TPE → HKG Jul 10, 08:40 UTCJul 10, 09:55 UTC1h 15m
2026-07-10 CPA420 HKG → TPE Jul 10, 05:50 UTCJul 10, 07:10 UTC1h 20m
2026-07-09 CPA361 HKG → HKG Jul 9, 11:45 UTCJul 10, 02:50 UTC15h 5m
2026-07-09 CPA754 - Jul 9, 08:55 UTCJul 9, 09:15 UTC20m
2026-07-09 CPA754 - Jul 9, 06:35 UTCJul 9, 07:05 UTC30m
2026-07-09 CPA755 - Jul 9, 03:40 UTCJul 9, 04:25 UTC45m
2026-07-09 CPA755 - Jul 9, 01:55 UTCJul 9, 02:10 UTC15m
2026-07-08 CPA421 TPE → HKG Jul 8, 10:00 UTCJul 8, 11:20 UTC1h 20m
2026-07-08 CPA420 HKG → TPE Jul 8, 07:05 UTCJul 8, 08:25 UTC1h 20m
2026-07-08 CPA543 - Jul 8, 01:30 UTCJul 8, 05:15 UTC3h 45m
2026-07-07 CPA542 HKG → HND Jul 7, 09:15 UTCJul 7, 13:00 UTC3h 45m
2026-07-07 CPA930 - Jul 7, 05:40 UTCJul 7, 07:15 UTC1h 35m
2026-07-07 CPA901 HKG → MNL Jul 7, 02:20 UTCJul 7, 03:55 UTC1h 35m
2026-07-06 CPA507 - Jul 6, 09:05 UTCJul 6, 12:25 UTC3h 20m
2026-07-06 CPA506 HKG → KIX Jul 6, 03:00 UTCJul 6, 06:10 UTC3h 10m
2026-07-05 CPA784 - Jul 5, 12:25 UTCJul 5, 12:40 UTC15m
2026-07-05 CPA785 - Jul 5, 02:20 UTCJul 5, 10:35 UTC8h 15m
2026-07-04 CPA974 - Jul 4, 21:50 UTCJul 4, 23:25 UTC1h 35m
2026-07-04 CPA913 - Jul 4, 14:00 UTCJul 4, 14:40 UTC40m
2026-07-04 CPA913 - Jul 4, 13:00 UTCJul 4, 13:20 UTC20m
2026-07-04 CPA411 - Jul 4, 06:35 UTCJul 4, 10:15 UTC3h 40m
2026-07-04 CPA410 HKG → ICN Jul 4, 02:05 UTCJul 4, 05:10 UTC3h 5m
2026-07-03 CPA505 - Jul 3, 14:25 UTCJul 3, 14:45 UTC20m
2026-07-03 CPA505 - Jul 3, 10:50 UTCJul 3, 13:50 UTC3h 0m
2026-07-03 CPA450 - Jul 3, 06:20 UTCJul 3, 09:05 UTC2h 45m
2026-07-03 CPA450 HKG → TPE Jul 3, 03:30 UTCJul 3, 05:00 UTC1h 30m
2026-07-02 CPA974 - Jul 2, 23:15 UTCJul 2, 23:35 UTC20m
2026-07-02 CPA974 - Jul 2, 22:00 UTCJul 2, 22:25 UTC25m
2026-07-02 CPA913 - Jul 2, 13:20 UTCJul 2, 15:10 UTC1h 50m
2026-07-02 CPA421 - Jul 2, 11:15 UTCJul 2, 11:35 UTC20m
2026-07-02 CPA421 - Jul 2, 10:15 UTCJul 2, 10:40 UTC25m

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

Mode-S 78921B frequently asked

What is Mode-S code 78921B?
78921B is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-HNS.
Where is Mode-S 78921B registered?
Mode-S code 78921B is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 78921B broadcasting right now?
Yes. Mode-S 78921B is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 78921B, octal 36111033, decimal 7,901,723.
What flights does 78921B operate?
Mode-S 78921B has broadcast 20 distinct callsigns, including CPA521, CPA450, CPA565, CPA974, CPA918.