Apparatus

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sensors Mode-S transponder

7801B4

ICAO 24-bit transponder address · allocated to China

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

Hex
7801B4
Octal
36000664
Decimal
7,864,756
Country
CN
Tail
B-HLU
Type
A333
No current signal · last broadcast 4h ago
Flights observed
378
Distinct callsigns
20
Country
CN
Last broadcast
4h ago

Last known position

Most recent position reported by Mode-S 7801B4.

Country allocation

The ICAO 24-bit address 7801B4 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
CPA965 - 11 2026-07-05
CPA964 - 11 2026-07-10
CPA332 - 10 2026-06-26
CPA501 Cathay Pacific 9 2026-06-17
CPA500 - 9 2026-06-17
CPA331 - 9 2026-06-26
CPA961 - 8 2026-06-15
CPA960 - 8 2026-06-25
CPA957 - 8 2026-07-05
CPA459 - 8 2026-06-28
CPA407 Cathay Pacific 8 2026-05-26
CPA953 Cathay Pacific 7 2026-06-12
CPA950 Cathay Pacific 7 2026-06-12
CPA912 - 7 2026-06-25
CPA489 Cathay Pacific 7 2026-06-12
CPA345 - 7 2026-06-25
CPA952 - 6 2026-07-05
CPA700 - 6 2026-06-29
CPA617 Cathay Pacific 6 2026-06-28
CPA458 - 6 2026-06-28

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 CPA986 - Jul 14, 02:50 UTCJul 14, 03:15 UTC25m
2026-07-13 CPA337 - Jul 13, 14:30 UTCJul 13, 14:55 UTC25m
2026-07-13 CPA337 - Jul 13, 12:00 UTCJul 13, 12:20 UTC20m
2026-07-13 CPA336 - Jul 13, 07:10 UTCJul 13, 07:30 UTC20m
2026-07-13 CPA503 - Jul 13, 01:15 UTCJul 13, 04:15 UTC3h 0m
2026-07-12 CPA502 HKG → KIX Jul 12, 08:55 UTCJul 12, 12:20 UTC3h 25m
2026-07-12 CPA948 HKG → HKG Jul 12, 00:30 UTCJul 12, 06:45 UTC6h 15m
2026-07-11 CPA337 - Jul 11, 17:15 UTCJul 11, 17:50 UTC35m
2026-07-11 CPA336 - Jul 11, 09:40 UTCJul 11, 09:50 UTC10m
2026-07-11 CPA336 - Jul 11, 07:10 UTCJul 11, 07:30 UTC20m
2026-07-10 CPA964 - Jul 10, 12:35 UTCJul 11, 01:55 UTC13h 21m
2026-07-10 CPA954 - Jul 10, 03:35 UTCJul 10, 10:35 UTC7h 0m
2026-07-09 CPA356 HKG → HKG Jul 9, 02:40 UTCJul 9, 08:30 UTC5h 50m
2026-07-06 CPA443 - Jul 6, 08:25 UTCJul 6, 09:50 UTC1h 25m
2026-07-06 CPA400 HKG → TPE Jul 6, 05:40 UTCJul 6, 07:15 UTC1h 35m
2026-07-06 CPA983 - Jul 6, 03:10 UTCJul 6, 04:05 UTC55m
2026-07-06 CPA982 - Jul 6, 00:40 UTCJul 6, 00:50 UTC10m
2026-07-05 CPA957 - Jul 5, 10:20 UTCJul 5, 11:00 UTC40m
2026-07-05 CPA952 - Jul 5, 04:55 UTCJul 5, 05:10 UTC15m
2026-07-05 CPA965 - Jul 5, 02:05 UTCJul 5, 02:20 UTC15m
2026-07-04 CPA964 - Jul 4, 13:15 UTCJul 4, 13:35 UTC20m
2026-07-04 CPA357 - Jul 4, 08:25 UTCJul 4, 09:10 UTC45m
2026-07-04 CPA356 - Jul 4, 02:50 UTCJul 4, 07:45 UTC4h 55m
2026-07-03 CPA449 KHH → HKG Jul 3, 23:35 UTCJul 4, 00:45 UTC1h 10m
2026-07-03 CPA448 - Jul 3, 14:40 UTCJul 3, 15:40 UTC1h 0m
2026-07-03 CPA945 - Jul 3, 12:15 UTCJul 3, 12:40 UTC25m
2026-07-03 CPA928 - Jul 3, 07:05 UTCJul 3, 07:25 UTC20m
2026-07-02 CPA957 HKG → HKG Jul 2, 05:05 UTCJul 2, 11:00 UTC5h 55m
2026-07-01 CPA931 - Jul 1, 14:05 UTCJul 1, 14:35 UTC30m
2026-07-01 CPA938 - Jul 1, 10:05 UTCJul 1, 10:25 UTC20m
2026-07-01 CPA987 - Jul 1, 08:05 UTCJul 1, 08:30 UTC25m
2026-07-01 CPA986 - Jul 1, 02:45 UTCJul 1, 03:00 UTC15m
2026-07-01 CPA632 - Jul 1, 00:15 UTCJul 1, 00:35 UTC20m
2026-06-30 CPA632 - Jun 30, 14:00 UTCJun 30, 23:35 UTC9h 35m
2026-06-30 CPA651 HKG → MAA Jun 30, 13:15 UTCJun 30, 13:30 UTC15m
2026-06-30 CPA957 - Jun 30, 10:40 UTCJun 30, 11:00 UTC20m
2026-06-30 CPA952 - Jun 30, 05:15 UTCJun 30, 05:35 UTC20m
2026-06-29 CPA421 - Jun 29, 09:44 UTCJun 29, 10:00 UTC15m
2026-06-29 CPA421 - Jun 29, 08:44 UTCJun 29, 09:10 UTC25m
2026-06-29 CPA420 HKG → TPE Jun 29, 06:05 UTCJun 29, 07:25 UTC1h 20m
2026-06-29 CPA700 - Jun 29, 02:54 UTCJun 29, 03:14 UTC20m
2026-06-29 CPA700 - Jun 29, 00:44 UTCJun 29, 02:14 UTC1h 30m
2026-06-28 CPA617 HKG → BKK Jun 28, 15:55 UTCJun 28, 17:19 UTC1h 25m
2026-06-28 CPA617 HKG → BKK Jun 28, 14:59 UTCJun 28, 15:14 UTC15m
2026-06-28 CPA459 - Jun 28, 12:50 UTCJun 28, 13:04 UTC15m
2026-06-28 CPA459 - Jun 28, 11:55 UTCJun 28, 12:15 UTC20m
2026-06-28 CPA458 - Jun 28, 09:34 UTCJun 28, 10:39 UTC1h 5m
2026-06-28 CPA750 - Jun 28, 04:20 UTCJun 28, 06:44 UTC2h 25m
2026-06-28 CPA705 HKG → BKK Jun 28, 00:15 UTCJun 28, 02:34 UTC2h 20m
2026-06-27 CPA991 - Jun 27, 13:55 UTCJun 27, 14:09 UTC15m

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

Mode-S 7801B4 frequently asked

What is Mode-S code 7801B4?
7801B4 is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-HLU.
Where is Mode-S 7801B4 registered?
Mode-S code 7801B4 is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 7801B4 broadcasting right now?
No active broadcast right now. Last signal was 4h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 7801B4, octal 36000664, decimal 7,864,756.
What flights does 7801B4 operate?
Mode-S 7801B4 has broadcast 20 distinct callsigns, including CPA965, CPA964, CPA332, CPA501, CPA500.